DAY 1 Flashcards by Catherine Losito

Match the radioactive isotope with its proper use: Cobalt-60
Heart scan in exercise
Measure water content of body
Kidney scan
Cancer therapy

Cancer therapy

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Which state of matter generally has the highest entropy?
Solid
Liquid
c. Gas
d. Plasma

d. Plasma

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Which principle explains why a refrigerator cools its contents?
Zeroth Law of Thermodynamics
Boyle’s Law
First Law of Thermodynamics
Second Law of Thermodynamics

Second Law of Thermodynamics

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For the reaction 2H₂ + O₂ → 2H₂O, ΔH = -484 kJ. How much energy is released when 5 moles of O₂ react completely?
1210 kJ
1215 kJ
c. -1215 kJ
d. -1210 kJ

d. -1210 kJ

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Which energy source is the most widely used worldwide today?
Nuclear
Wind
c. Solar
d. Coal

d. Coal

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The combustion efficiency of a fuel is mainly determined by:
Color of flame
Volume of fuel
c. Specific heat of fuel
d. Air-fuel ratio

d. Air-fuel ratio

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Which of the following hazard categories is NOT explicitly included in an SDS?
Physical hazards
Health hazards
c. Environmental hazards
d. Biological hazards

d. Biological hazards

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Which section of an SDS would provide information on whether a chemical is biodegradable?
Section 8
Section 14
c. Section 10
d. Section 12

d. Section 12

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Identify the following symbol (dead fish):
health hazard
serious health hazard
acute toxicity
hazardous to environment

hazardous to environment

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Which hydrocarbon has a vapor density of 29 relative to hydrogen?
Butene
Pentane
c. Pentene
d. Butane

d. Butane

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A solution has an osmotic pressure of 12 atm at a temperature of 298K. The solute is sucrose (molar mass = 342 g/mol. What is the mass fraction of sucrose in the solution?
0.085
0.125
c. 0.235
d. 0.168

d. 0.168

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If a reaction is exergonic, what can be said about ΔG?
ΔG > 0
G is maximum
c. ΔG = 0
d. ΔG < 0

d. ΔG < 0

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What is the purpose of digestion in gravimetric analysis?
To dissolve impurities in the precipitate
To increase the solubility of the precipitate in solution
To speed up the reaction by increasing temperature
To promote the growth of larger and purer precipitate particles for easier filtration

To promote the growth of larger and purer precipitate particles for easier filtration

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What is the unit of the modulus of elasticity?
Joule (J)
Newton (N)
c. Watt (W)
d. Pascal (Pa)

d. Pascal (Pa)

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Which of the following gases has the highest global warming potential (GWP) over a 100-year period?
Carbon dioxide
Nitrogen oxides
c. Methane
d. Sulfur hexafluoride

d. Sulfur hexafluoride

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What makes PM2.5 more dangerous to human health compared to PM10?
PM2.5 is heavier and settles faster, causing more localized damage.
PM10 is chemically inert, while PM2.5 is highly reactive.
PM2.5 is always composed of toxic substances, while PM10 is not.
PM2.5 particles can enter deeper into the lungs and even the bloodstream.

PM2.5 particles can enter deeper into the lungs and even the bloodstream.

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Company A consumes 300,000 kWh of electricity with an emission factor of 0.60 kg CO₂/kWh, while Company B consumes 250,000 kWh of electricity with an emission factor of 0.24 kg CO₂/kWh. What is the total Scope 2 CO₂ emissions from both companies?
180,000 kg CO₂
200,000 kg CO₂
c. 220,000 kg CO₂
d. 240,000 kg CO₂

d. 240,000 kg CO₂

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Which formula is used to calculate chlorine demand in water treatment?
Chlorine demand = Chlorine residual - Chlorine applied
Chlorine demand = Chlorine residual × Chlorine applied
Chlorine demand = Chlorine applied + Chlorine residual
Chlorine demand = Chlorine applied - Residual chlorine

Chlorine demand = Chlorine applied - Residual chlorine

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The mass of a proton or neutron is approximately times that of an electron.
1736
1700
1900
1836

1836

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Which of the following is a semi-conductor?
B
Si
Ge
All of these

All of these

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A solution of HCl has a specific gravity of 1.12 and contains 23.81% HCl by weight. How many grams of HCl are present in each milliliter of the solution?
1.2
13.2
12.6
0.27

0.27

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Which of the following has the highest boiling point?
water
benzene
toluene
phenol

phenol

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Which of the following is the most polar bond?
N-O
C-C
C-H
H-F

H-F

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Dispersion of a solid or liquid particles of microscopic size in a gas media such as smoke is
a soot
a mist
a vapor
an aerosol

an aerosol

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Which metal causes browning color in water? chromium aluminum copper iron

iron

What is the frequency of light that has a wavelength of 432 nm? 1.44x103 Hz 8.39x1011 Hz 1.30x1020 Hz 6.94x1014 Hz

6.94x1014 Hz

Which type of orbital is not allowed? 1s 4p 5f 2d

Which of the following has the largest atomic radius? Be Sr Mg Ba

An element obtained commercially from sea water and salt brines is aluminum potassium beryllium magnesium

magnesium

Dispersion of solid or liquid particles of microscopic size in a gas media such as a smoke is A soot a vapor a mist an aerosol

an aerosol

Which hybrid orbital set and molecular geometry are incorrect? sp2 – trigonal planar sp3 – tetrahedral sp – linear sp2 – trigonal bipyramidal

sp2 – trigonal bipyramidal

How many moles of H2 are required to completely reduce 15 grams of the unsaturated hydrocarbon? CH2=CHCH2CH=CH2 + 2H2= CH3CH2CH2CH2CH3 1.163 mol H2 1.023 mol H2 0.837 mol H2 0.442 mol H2

0.442 mol H2

Are the following processes exothermic or endothermic? 1. When solid KBr is dissolved in water, the solution gets colder. 2. Natural gas (CH4) is burned in a furnace. 3. When concentrated H2SO4 is added to water, the solution gets very hot. 4. Water is boiled in a teakettle. exothermic, exothermic, endothermic, endothermic endothermic, exothermic, endothermic, endothermic exothermic, exothermic, exothermic, endothermic endothermic, exothermic, exothermic, endothermic

endothermic, exothermic, exothermic, endothermic

Arrange the following in order of increasing radius and increasing ionization energy: N+, N, N- Radius: N- < N < N+, Ionization Energy: N- < N < N+ Radius: N+ < N < N-, Ionization Energy: N+ < N < N- Radius: N- < N < N+, Ionization Energy: N+ < N < N- Radius: N+ < N < N-, Ionization Energy: N- < N < N+

Radius: N+ < N < N-, Ionization Energy: N- < N < N+

Classify these as kinetic or potential energy. 1. Water held by a dam. 2. A speeding train. 3. A book on its edge before falling. 4. A falling book. 5. Electric current in a light bulb. kinetic, kinetic, potential, kinetic, kinetic kinetic, kinetic, potential, kinetic, potential potential, kinetic, potential, kinetic, potential potential, kinetic, potential, kinetic, kinetic

potential, kinetic, potential, kinetic, kinetic

Which of the following particles has the smallest mass? proton neutron deuteron positron

positron

For each of the following, identify the radiation emitted. 1. Beryllium-10 changes to boron-10. 2. Europium-151 changes to europium-151. 3. Thallium-195 changes to mercury-195. 4. Plutonium-239 changes to uranium-235. beta, positron, gamma, beta alpha, gamma, neutron, beta alpha, neutron, beta, positron beta, gamma, positron, alpha

beta, gamma, positron, alpha

Uranium-235 undergoes a series of alpha particle and beta particle productions to end up as lead-207. How many alpha particles and beta particles are produced in the complete decay series? 6, 3 8, 6 5, 5 7, 4

7, 4

In coal combustion, what is the primary factor that determines the amount of excess air required? Moisture content Ash content Carbon content Volatile matter content

Volatile matter content

Which statement best describes the second law of thermodynamics? Work is equal to heat transfer in a cyclic process. Energy cannot be created or destroyed. The enthalpy change of a reaction is independent of the path taken. The total entropy of an isolated system can never decrease.

The total entropy of an isolated system can never decrease.

Which of the following reactions is primarily responsible for the production of energy in a nuclear reactor? Electrochemical oxidation of hydrogen Nuclear fusion of hydrogen isotopes Combustion of fossil fuels Nuclear fission of uranium-235

Nuclear fission of uranium-235

In a gas turbine, the working fluid is typically: Nitrogen Helium Steam Air

Air

What type of polymerization produces polyethylene? Co-polymerization Step-growth polymerization Condensation polymerization Addition polymerization

Addition polymerization

The main advantage of composite materials is: High electrical conductivity Increased brittleness Low density only High strength-to-weight ratio

High strength-to-weight ratio

Which SDS section provides information on proper personal protective equipment (PPE)? Section 13 – Disposal Considerations Section 3 – Composition/Information on Ingredients Section 10 – Stability and Reactivity Section 8 – Exposure Controls/Personal Protection

Section 8 – Exposure Controls/Personal Protection

Identify the following hazard symbol Identifies oxidizers. Oxidizers are chemicals that facilitate burning or make fires burn hotter and longer. Materials causing skin corrosion/burns or eye damage on contact, or that are corrosive to metals. Flammable materials or substances liable to self ignite when exposed to water or air (pyrophoric), or which emit flammable gas. An immediate skin, eye or respiratory tract irritant, or narcotic.

An immediate skin, eye or respiratory tract irritant, or narcotic.

Which of the following represents a homogenous mixture? Ice A silver-plated spoon 3-in-1 coffee powder Clean fresh air

Clean fresh air

What is the chemical symbol for the perchlorate ion? ClO- ClO2- ClO3- ClO4-

ClO4-

The electron-group geometry of H2O is: Trigonal planar Trigonal pyramidal Bent Tetrahedral

Tetrahedral

Define a salt in terms of acid and base. A salt is a compound that follows Le Chatelier’s Principle in reactions with other compounds. All of these A salt is a compound formed when the nucleus of a hydrogen tom enters a quantity of water. A salt is a compound (other than water) produced by the reaction of an acid and a base.

A salt is a compound (other than water) produced by the reaction of an acid and a base.

Which of the following acids would be most suitable for preparing a buffer of pH 3.1? Hydrogen peroxide, pKa = 11.65 Propanoic acid, pKa = 4.874 Cyanoacetic acid, pKa = 2.472 Sulfanilic acid, pKa = 3.232

Sulfanilic acid, pKa = 3.232

Define a salt in terms of acids and bases. A salt is a compound that follows Le Chatelier principle in reactions with other compounds. All of these A salt is a compound formed when the nucleus of a hydrogen atom enters a quantity of water. A salt is a compound (other than water) produced by the reaction of acid and a base.

A salt is a compound (other than water) produced by the reaction of acid and a base.

Which of the following is not conserved in any process? Mass Energy Momentum Entropy

Entropy

The Nikolaus Otto Jacobus Clapeyron William Clausius Walther Nernst

Walther Nernst

This is the pressure exerted by the gas molecules that are in equilibrium with the liquid. Partial pressure Atmospheric pressure Total pressure Vapor pressure

Vapor pressure

The Clapeyron Equation gives the slope: dV/dT dT/dP dT/dV dP/dT

dP/dT

What is the Clapeyron Equation? Any of these It postulates that the colligative properties, freezing point depression, boiling point elevation, osmotic pressure, and vapor pressures are all dependent on the number f particles in the solution and any change thereof is described. It postulates that if two components systems consisting of solid and liquid phases are miscible in the liquid state and immiscible in the solid state, only the pure solid systems will separate out on cooling solutions. It postulates that if the temperature and pressure are both change in such a way as to keep the chemical potentials of two phases equal to each other, the rates of change are given by the equation.

It postulates that if the temperature and pressure are both change in such a way as to keep the chemical potentials of two phases equal to each other, the rates of change are given by the equation.

For a particular chemical reaction, ΔH˚ is positive and ΔS˚ is negative. Which of the following statements about the spontaneity of the reaction under standard conditions is TRUE? The reaction will be spontaneous only if the magnitude of ΔH˚ is large enough to cover the unfavorable entropy change. The reaction will be spontaneous only if the magnitude of ΔS˚ is large enough to overcome the unfavorable enthalpy change. The reaction will be spontaneous regardless of the magnitudes of ΔH˚ and ΔS˚. The reaction cannot be spontaneous.

The reaction cannot be spontaneous.

Choose the process/es that occur/s with a decrease in entropy. Dissolving salt in water Sublimation of dry ice Boiling of water Freezing of water

Freezing of water

Which of the following thermodynamic expression describes a spontaneous process under constant temperature and pressure? ∆G = 0 ∆S = 0 ∆S < 0 ∆G < 0

∆G < 0

Which among the following can cause the greatest damage to a material assuming that all of them can penetrate it equally? 100 rad Gamma rays 100 rad Beta Emission 100 rad Neutron Emission 100 rad Alpha Emission

100 rad Alpha Emission

Which among the following radioactive nuclides is often attributed as the greatest source of radiation that affects most of the population? Strontium-90 Americium-241 Polonium-218 Radon-222

Radon-222

A nuclear chemist from the Philippine Nuclear Research Institute is dissolving a sample of NaCl, that contains the radioactive sodium-24, in 100 mL aliquot of aqueous sodium nitrate. The mixture was subsequently cooled in order to recrystallize the sodium nitrate salt. Which among the following is true? The chloride anions will selectively reform an ionic bond with the sodium- 24 cation The sodium nitrate crystals should be non-radioactive All of the sodium-24 cations would specifically bond with the nitrate ion due to its electron-distribution capability Some of the anions will randomly bond with the sodium-24 nuclide

Some of the anions will randomly bond with the sodium-24 nuclide

It is known as Water Quality Guidelines and General Effluent Standards of 2016. DAO 34 DAO 35 RA 9275 DAO No. 2016-08

DAO No. 2016-08

Gas responsible for the rotten egg odor of wastewater. ammonia amines mercaptans hydrogen sulfide

hydrogen sulfide

Sodium ions contribute to which characteristics of water pH color hardness total dissolved solids

total dissolved solids

In determination of BOD, the reaction takes place in the dark because The microorganisms are sensitive to light. Oxygen is sensitive to light. The reaction is enhanced in the dark. Algae may be present and produce oxygen.

Algae may be present and produce oxygen.

Which of the following is not a physical characteristic of wastewater? odor turbidity color hardness

hardness

Which of the following is NOT a secondary treatment process? Trickling filter Activated sludge process Anaerobic digestion Chlorination

Chlorination

Pick out the wrong statement. The concentric atmosphere layer just above troposphere is called stratosphere, which is rich in ozone. Mesosphere is characterized by very low atmosphere pressure and low temperature. Troposphere is a dusty zone containing water vapor and clouds. The radio waves used in the long-distance radio communication are reflected to earth by stratosphere.

The radio waves used in the long-distance radio communication are reflected to earth by stratosphere.

The removal of dissolved organic carbon (DOC) in water treatment is typically done using: Ozonation Sand filtration Reverse osmosis Activated carbon adsorption

Activated carbon adsorption

Sludge from primary settling tanks is mostly composed of: Inorganic salts Biologically active microorganisms Heavy metals Settleable organic solids

Settleable organic solids

Which gas has the highest global warming potential (GWP)? CO₂ N₂O CH₄ SF₆

SF₆

In treating turbid water, a popular coagulant is calcium sulfate pulverized coke chlorine ferric sulfate

ferric sulfate

Which greenhouse gas has the highest global warming potential (GWP) over a 100-year period according to the IPCC? Carbon dioxide Methane Nitrous oxide Sulfur hexafluoride

Sulfur hexafluoride

How many forms of nitrogen present in wastewater? 4 3 2 5

This metal is alloyed with steel to give it corrosion resistance properties, resulting in stainless steel. vanadium magnesium molybdenum chromium

chromium

__________ are composed of ceramics and metals Cement Metal matrix Glass Cermets

Cermets

Which of the following is not a ceramic? Glass Graphite Diamond Carbon

Carbon

Wood is composed of chains of cellulose molecules bonded together by another natural polymer called cellulose plastic latex lignin

lignin

Materials composed of more than one material type and are designed to display a combination of the best characteristics of each component material. Polymers Ceramics Metals Composites

Composites

Materials that have electrical properties that are intermediate between the metals or metal alloys and ceramics or polymers metalloid porcelain insulator semiconductor

semiconductor

The _____________, sometimes called the breakdown strength, represents the magnitude of an electric field necessary to produce breakdown. Avalanche breakdown Dielectric constant Working voltage Dielectric strength

Dielectric strength

Ionic bonding was supposed to be believed at first as Sharing of electrons of nonmetallic and nonmetallic atoms Sharing of electrons of metallic and nonmetallic atoms Transfer of electrons of nonmetallic and nonmetallic atoms Transfer of electrons of metallic and nonmetallic atoms

Transfer of electrons of metallic and nonmetallic atoms

This refers to a crystal system with two equal axes with one angle equal to 120o Tetragonal Rhombohedral Orthorhombic Hexagonal

Hexagonal

What two crystal structures have the same total number of atoms inside? FCC and HCP BCC and CCP BCC and HCP CCP and FCC

CCP and FCC

In an FCC unit cell, the number of atoms per unit cell is: 2 6 1 4

Which of the following is NOT a correct unit of energy? Joule Calorie Watt d. Kilowatt-hour

Watt

Which fossil fuel has the highest carbon content? Natural gas Petroleum c. Coal d. Methanol

c. Coal

Which of the following has the highest molar heat capacity? He (g) N₂ (g) c. H₂O (l) d. C (graphite)

c. H₂O (l)

What happens to the internal energy of an ideal gas in an isothermal expansion? It increases It decreases c. It remains constant d. It depends on the pressure

c. It remains constant

The Gibbs free energy change of a reaction at equilibrium is: Positive Negative Zero Dependent on the activation energy

Zero

A reaction has ΔH = -200 kJ and ΔS = -300 J/K. At what minimum temperature does the reaction become non-spontaneous? 500 K 750 K c. 667 K d. 1000 K

c. 667 K

Which law explains why no engine can be 100% efficient? Zeroth Law of Thermodynamics First Law of Thermodynamics Second Law of Thermodynamics Third Law of Thermodynamics

Second Law of Thermodynamics

The entropy of a perfectly ordered crystalline substance at 0 K is: Infinite Negative c. Zero d. Equal to its enthalpy

c. Zero

Which type of energy is associated with the breaking of chemical bonds? Kinetic energy Thermal energy c. Activation energy d. Electrical energy

c. Activation energy

A fuel has an energy content of 45 MJ/kg. If an engine operates at 30% efficiency, how much fuel is required to generate 500 MJ of useful energy? 12 kg 45 kg c. 37 kg d. 55 kg

c. 37 kg

Which of the following elements is most used in solar cells? Carbon Lithium c. Silicon d. Uranium

c. Silicon

Which chemical process is responsible for energy generation in fuel cells? Combustion Electrolysis c. Oxidation-reduction d. Polymerization

c. Oxidation-reduction

Which of the following energy sources is considered renewable? Coal Natural gas c. Biomass d. Uranium

c. Biomass

Which greenhouse gas is the most effective at trapping heat? Carbon dioxide Nitrogen c. Methane d. Oxygen

c. Methane

Which gas law explains why car tires expand in hot weather? Boyle’s Law Avogadro’s Law c. Charles’ Law d. Dalton’s Law

c. Charles’ Law

Which gas is commonly found in coal mines and is known as "firedamp" due to its flammability? Carbon dioxide (CO2) Nitrogen (N2) c. Methane (CH4) d. Hydrogen sulfide (H2S)

c. Methane (CH4)

The calorific value of methane (CH4) is approximately: 20 MJ/kg 35 MJ/kg c. 50 MJ/kg d. 70 MJ/kg

c. 50 MJ/kg

Which regulatory body enforces SDS compliance in the workplace? FDA EPA c. OSHA d. NIOSH

c. OSHA

Which section of an SDS provides information on recommended protective measures and PPE? Section 5 Section 6 c. Section 8 d. Section 10

c. Section 8

Which of the following hazard symbols is NOT real? Corrosive: A liquid dripping onto a hand Toxic: A skull and crossbones Radioactive: A flame with a circle Explosive: A shattered object

Radioactive: A flame with a circle

Which of the following pH values corresponds to a highly corrosive acid? a. 6 b. 4 c. 2 d. 8

c. 2

Which of the following should NOT be disposed of in the sink? Diluted sodium chloride solution 0.1M acetic acid Organic solvents like ethanol and acetone Diluted sodium hydroxide

Organic solvents like ethanol and acetone

Which of the following pairs of chemicals should never be stored together due to the risk of explosive reaction? Sodium hydroxide (NaOH) and water Hydrogen peroxide (H2O2) and iron filings Acetone and nitric acid Hydrochloric acid (HCl) and sodium chloride (NaCl)

Acetone and nitric acid

Which of the following physical properties is important for determining a chemical’s flammability? Solubility Viscosity c. Flash point d. Specific gravity

c. Flash point

The term "Threshold Limit Value (TLV)" refers to: The concentration below which no toxic effects occur The maximum concentration allowed in drinking water The maximum workplace exposure limit The concentration at which a chemical ignites

The maximum workplace exposure limit

GHS stands for: General Hazard System Global Hazard Symbols Globally Harmonized System Generalized Hazard Standard

Globally Harmonized System

Identify the symbol (circle with flame) flammable corrosive c. oxidizing d. toxic

c. oxidizing

Which element was first used in the experimental discovery of the Bose-Einstein Condensate (BEC) in 1995? Helium (He) Sodium (Na) c. Rubidium (Rb) d. Cesium (Cs)

c. Rubidium (Rb)

An ideal gas undergoes isothermal expansion at a temperature of 350 K. The gas expands from an initial volume of 2.0 L to a final volume of 5.0 L. The heat absorbed by the gas during this process is 500 J. What is the change in entropy (ΔS) of the system? 1.25 J/K 1.67 J/K c. 1.43 J/K d. 1.89 J/K

c. 1.43 J/K

What is the change in internal energy of a closed system after completing a cyclic process? Equal to the heat added to the system Equal to the work done by the system Zero Depends on the efficiency of the cycle

Zero

A 50 mL solution of 1 M HCl is mixed with 50 mL of 1 M NaOH. The initial temperature of both solutions is 25.0°C, and the final temperature after mixing is 31.2°C. Given that the density of the solution is 1 g/mL and specific heat capacity is 4.18 J/g-°C, calculate the heat of mixing. -20880 J -10440 J c. -51800 J d. -26040 J

c. -51800 J

A 2 kg metal block is heated, increasing its temperature from 25°C to 75°C. The specific heat capacity of the metal is 104.5 J/kg-K. What is the amount of heat energy absorbed by the metal? 7450 J 8900 J c. 10450 J d. 12500 J

c. 10450 J

Which process is always exergonic? Electrolysis of water Photosynthesis c. Combustion of methane d. Formation of ozone

c. Combustion of methane

A 0.03 mol solution of HCl is used to completely titrate an unknown amount of NaOH. How many moles of NaOH were present in the analyte? 0.015 mol 0.045 mol c. 0.030 mol d. 0.060 mol

c. 0.030 mol

A solution has an absorbance of 0.5 when measured in a 1 cm cuvette. If the concentration is doubled, what will be the new absorbance? 0.25 0.5 c. 1.00 d. 2.00

c. 1.00

A solution has an absorbance of 1.2 when measured in a 1 cm path length cuvette. What will happen to the absorbance if the path length is increased to 2 cm while keeping the concentration constant? Absorbance will stay the same Absorbance will be halved Absorbance will double Absorbance will decrease to 1.0

Absorbance will double

A solution has an absorbance of 0.301 when measured using a spectrophotometer. What is its transmittance (T)? 0.25 0.3 c. 50% d. 75%

c. 50%

What is the main requirement for a precipitate to be suitable for gravimetric analysis? It must be highly soluble in water It should be volatile at room temperature It must be a pure, stable, and easily filterable solid It should dissolve easily in strong acids

It must be a pure, stable, and easily filterable solid

Which material typically has the highest modulus of elasticity? Rubber Aluminum c. Steel d. Plastic

c. Steel

What is a key advantage of thermoplastics over thermosetting plastics? Higher resistance to heat and chemicals Stronger mechanical properties Ability to be remolded multiple times Permanent cross-linked structure

Ability to be remolded multiple times

A composite material consists of 40% matrix by weight. What is the weight fraction of the reinforcement in the composite? 0.4 0.5 c. 60% d. 75%

c. 60%

The concentration of methane in the atmosphere is 1875 ppb, and its concentration increases by 7 ppb per year. The total mass of the atmosphere is 2.82×1018 kg. If global methane emissions are 600 teragrams (TG) per year, what is the lifetime of methane in the atmosphere in years? 15.7 years 12.0 years c. 8.8 years d. 6.8 years

c. 8.8 years

Which of the following is an effective method for removing phosphorus from water in wastewater treatment? Boiling the water to evaporate phosphorus Adding chlorine to oxidize phosphorus Chemical precipitation using aluminum or iron salts Using UV radiation to break down phosphorus compounds

Chemical precipitation using aluminum or iron salts

An ion exchange system is used to soften 200 L of water, which has a hardness of 100 mg/L as CaCO3. The system requires 1000 L of regeneration water to restore the resin using a salt (NaCl) solution. If2.5 mg of NaCl is required per mg of CaCO3, how many kg of salt are needed for regeneration? 0.10 kg 1.00 kg c. 0.25 kg d. 2.50 kg

c. 0.25 kg

Deuterium or heavy hydrogen has an atomic no. of 1 and a mass of 3 1 2 4

Describe the geometry of CH2Cl2, dichloromethane. Is it a polar or a nonpolar molecule? pyramidal, polar pyramidal, nonpolar tetrahedral, polar tetrahedral, nonpolar

tetrahedral, polar

The bond angle in CH4 is approximately 90˚ 105˚ 109˚ 120˚

109˚

How many valence electrons are involved in writing the Lewis structure of AsF3? 5 21 26 8

To increase the solubility of sugar in water, you must stir the solution vigorously pulverize the sugar particles before adding them to the water heat the solution evaporate the water

heat the solution

Calculate the pOH of a 0.020 M HCl solution 1.7 2.8 12.3 11.2

12.3

A weak acid, HA, has a Ka of 1x10-5. If 0.10 mole of this acid is dissolved in one liter of water, the percentage of acid dissociated at equilibrium is closest to 0.001 0.999 0.01 0.999

0.01

Calculate the ionization constant for 0.1 M nitrous acid that is 6.5% ionized 5.6 X 10-2 1.8 X 10-5 4.5 X 10-4 1.8 X 10-5

4.5 X 10-4

Which of the following will evaporate easily in a dry cloth? water acetone diethyl ether oil

diethyl ether

It is an explanation of the general principles of certain phenomena with considerable evidence or facts to support it. hypothesis scientific law theory scientific method

theory

Cathode rays are protons neutrons electrons nucleons

electrons

Quicklime is CaCO3 Na2CO3 CaO Ca(OH)2

CaO

When an atom or ion possesses one or more unpaired electron, the substance is magnetic ferromagnetic paramagnetic ferromagnetic

paramagnetic

Which of the following is a chemical change?. Water boiling Alcohol evaporating Natural gas burning Ice melting

Natural gas burning

Dalton’s atomic theory consisted of all the following postulates except Atoms of different elements have different properties Elements are composed of indivisible particles called atoms With gases, the volumes consumed and produced are in ratios of small whole numbers Atoms combine in fixed ratios of whole numbers

With gases, the volumes consumed and produced are in ratios of small whole numbers

Which of the following atoms have the highest electron affinity? Na Br Cl S

The melting point and boiling point of halogens Increases with increasing atomic number decreases with increasing mass number Increases with increasing mass number decreases with increasing mass number

Increases with increasing mass number

What is the energy in J of a photon of electromagnetic radiation that has a wavelength of 9.0 m? 6x10-23 2.7x109 2.2x10-26 4.5x1025

2.2x10-26

Which of the following is the lightest? alpha particle proton beta particle hydrogen

beta particle

It consist of high-energy photons, that is electromagnetic radiation of very short wavelength alpha rays beta rays gamma rays radioactive decay

gamma rays

Which of the following types of nuclear decay results in man increase in the nuclear charge? alpha emission positron emission beta emission gamma emission

beta emission

Which isotope is particularly useful for both diagnostic and therapeutic work with the thyroid gland? cobalt-60 technetium-99 iodine-131 tritium

iodine-131

Match the radioactive isotope with its proper use: Mercury-197 Heart scan in exercise Measure water content of body Kidney scan Cancer therapy

Kidney scan

A rock contains 0.688 mg 206Pb for every 1.000 mg 238U present. Assuming that no lead was originally present, that all the 206Pb formed over the years has remained in the rock, and that the number of nuclides in intermediate stages of decay between 238U and 206Pb is negligible, calculate the age of the rock. 7.5x107 years 1.9x108 years 3.8x109 years 2.1x107 years

3.8x109 years

What particle is emitted in the decay chain represented by 146C → 147N? Alpha Positron Beta Gamma

Beta

A reported synthesis of the transuranium element bohrium (Bh) involved the bombardment of berkelium-249 with neon-22 to produce bohrium-267. The half-life of bohrium-267 is 15.0 seconds. If 199 atoms of bohrium-267 could be synthesized, how much time would elapse before only 11 atoms of bohrium-267 remain? 50 s 79 s 63 s 44 s

63 s

Which type of coal has the highest carbon content and energy density? Peat Bituminous Anthracite Lignite

Anthracite

Microwaves are a form of electromagnetic radiation that is used for the rapid heating of foods. What is the frequency of a microwave with a wavelength of 5.8 cm? 9.4E9 /s 1.7E9 /s 5.2E9 /s 3.6E9 /s

5.2E9 /s

Balance the chemical equation given K4Fe(CN)6 + H2SO4 + H2O = K2SO4 + FeSO4 + (NH4)2SO4 + CO 1,6,6,2,1,2,6 2,6,6,2,1,3,6 1,6,6,2,1,3,6 6,3,1,2,6,6,1

1,6,6,2,1,3,6

Which property measures a material’s resistance to deformation under load? Toughness Ductility Elastic modulus Hardness

Elastic modulus

Which atmospheric pollutant is most closely associated with photochemical smog? Sulfur dioxide Carbon monoxide Ozone Particulate matter

Ozone

Cathode rays May be positively or negatively charged Are of form of electromagnetic radiation similar to visible light Have properties identical to β particles Have masses that depend on the cathode that emit them

Have properties identical to β particles

Whatis the correct name of of Fe2(SO4)3? Ferric sulfite Ferrous sulfite Ferric sulfate Ferrous sulfate

Ferric sulfate

Which of the following atoms has the largest size? Na H Rb Li

What is the molecular geometry of NH4+? Bent Trigonal pyramidal Tetrahedral Trigonal planar

Tetrahedral

Which of the following pairs will form a buffer solution in the course of a titration? Nitric acid, sodium hydroxide Sulfuric acid, potassium hydroxide Acetic acid, sodium hydroxide Hydrochloric acid, potassium hydroxide

Acetic acid, sodium hydroxide

When a can of soda is opened and CO2 is released to the atmosphere, what is the resultant pH of the soda? decreases all of these increases the same

increases

For a real gas, what causes the deviation from the ideal pressure at a molecular level? Energy is lost for each collision against the sides of the container Energy is lost due to the collision of molecules with one another Intermolecular forces of attraction of the molecules with one another Molecules randomly hit the sides of the wall with less force than usual

Intermolecular forces of attraction of the molecules with one another

The Clausius-Clapeyron Equation does NOT apply to: S-V equilibrium L-V equilibrium S-L equilibrium None of these

S-L equilibrium

In a process involving osmosis, at equilibrium, the chemical potential of the pure solvent side should be ____________ the chemical potential of the side with solute. Less than More than Equal to Can’t be determined

Equal to

The boiling point of two immiscible liquids is Higher than the boiling point of either liquid. Between the boiling points of the two liquids. Lower than the boiling point of either of the liquids. Equal to the boiling point of one of the liquids.

Lower than the boiling point of either of the liquids.

Fill in the blank: Protium is a/an _____ of Hydrogen while Protium, Deuterium, and Tritium comprise the Hydrogen ____________ Isotope, Isotopes Nuclide, Nuclides Nuclide, Isotopes Isotope, Nuclides

Nuclide, Isotopes

Which among the following radioactive decay series does not occur naturally? Actinium Series Uranium Series Neptunium Series Thorium Series

Neptunium Series

Which among the following can detect the neutrons produced by U-235 undergoing nuclear fission? A Geiger counter containing Fluorine Gas A Scintillation Counter containing Zinc Sulfide and Xenon A Geiger Counter containing Argon and Boron Trifluoride A Scintillation Counter containing Tungsten Carbide

A Geiger Counter containing Argon and Boron Trifluoride

Which among the following is the phosphor of a scintillation counter intended for the detection of gamma radiation? Zinc Sulfide Metastable Technetium-99 NaI Crystals containing Thallium (II) Iodide Buckminsterfullerene

NaI Crystals containing Thallium (II) Iodide

Define atomic mass unit. The mass of one Carbon-12 atom One half the mass of a Carbon-14 mole One-twelfth the mass of a Carbon-12 atom One-twelfth the mass of 6.022x1023 atoms of Carbon-14

One-twelfth the mass of a Carbon-12 atom

Based on the units commonly used in Nuclear Chemistry, which among the following measures the amount of energy acquired by an electron when it falls through an electric potential difference of 1 volt? Ci Bq eV Gy

Which among the following statements regarding Nuclear Fusion and Nuclear Fission is False? Nuclear fusion involves the amalgamation of lighter nuclei in order to form heavier, stabler nuclei The maximum binding energy per nucleon can be achieved at a mass number of 60 Nuclear fusion releases more energy than Nuclear fission on a per nucleon basis The fragmentation of heavier nuclides displays a relatively plateau decrease in binding energy when compared to the reverse

Nuclear fusion releases more energy than Nuclear fission on a per nucleon basis

The Bataan Nuclear Power Plant is planned to be retrofitted in hopes of using it for the first time. One point of concern is the material that would be used in the outer portions of the room housing the fuel rods. If the radiation coming from the fuel rods would be a strong beta emission, which material among the following should be utilized? 1 cm of Aluminum 7.5 m of Concrete 8 mm of Lucite 35 m of Lead

8 mm of Lucite

Across the three most notorious accidents regarding nuclear power plants: Three Mile Island, Chernobyl, and Fukushima, what is the most common cause for their failure that led to several environmental problems? A leak in the fuel rods initiating an explosion Bursting of reactor due to uncontrolled pressurized steam Loss of proper cooling and/or moderator Run-off chain reactions of the fissile material

Loss of proper cooling and/or moderator

Which among the following statements regarding Nuclear Fission is FALSE? Nuclear Fission is a nuclear reaction in which a heavy nucleus splits into lighter nucleus and energy is released A series of self-sustaining nuclear fissions is called a nuclear chain reaction Nuclear Fission is the main proponent of nuclear power plants, atomic bombs, and hydrogen bombs Critical mass is the minimum amount of a fissionable material that can cause a nuclear chain reaction

Nuclear Fission is the main proponent of nuclear power plants, atomic bombs, and hydrogen bombs

Class of water intended for primary contact recreation such as bathing, swimming, skin diving, etc. Class AA Class A Class B Class C

Class B

Which of the following apparatus is not used in measuring turbidity? Jackson Turbidimeter Secchi Disk Depth Photoelectric Colorimeter none of these

Photoelectric Colorimeter

Removal of all settleable particles rendered settleable under the influence of gravity, basically the theory of gravity under the influence of which all particles heavier than water tend to settle down. screening flotation sedimentation flocculation

sedimentation

Water treatment that destroys disease-causing bacteria, nuisance bacteria, parasites and other organisms and removes soluble irons, manganese and hydrogen sulfide from water. disinfection flocculation chlorination coagulation

chlorination

A code for plastics used for food wrapping, trash bags, grocery bags and baby diapers. 2 3 4 5

Ecological Solid Waste Act of 2000 is otherwise known as RA 6969 RA 8749 RA 9003 RA 9275

RA 9003

A global treaty that aims to diminish and eventually phase out chlorofluorocarbons. Stockholm Convention Kyoto Protocol Montreal Protocol none of these

Montreal Protocol

Collective term for the initial POPs identified by the Stockholm Convention Dirty 12 12 POPs Dirty Dozens EDCs

Dirty Dozens

The rate at which temperature in the atmosphere changes with altitude is called temperature change thermal rate lapse rate vertical rate

lapse rate

What is the primary purpose of coagulation in water treatment? Remove dissolved gases Kill bacteria Destabilize suspended particles Remove dissolved salts

Destabilize suspended particles

What is the role of a flocculant in water treatment? Reduces pH levels Increases microbial activity Helps in aggregation of fine particles Removes dissolved salts

Helps in aggregation of fine particles

Reverse osmosis (RO) is mainly used to remove: Suspended solids Bacteria Dissolved salts Heavy metals

Dissolved salts

What is the main drawback of using activated carbon in water treatment? It releases harmful byproducts It requires high energy input It has a limited adsorption capacity and needs frequent replacement It is only effective against suspended solids

It has a limited adsorption capacity and needs frequent replacement

What is the most common method for removing nitrates from water? Chemical precipitation Flocculation Ion exchange Coagulation

Ion exchange

The main function of a rapid sand filter is to: Sterilize water Remove color Remove remaining turbidity after sedimentation Remove hardness

Remove remaining turbidity after sedimentation

Which of the following is the best method to remove arsenic from water? Boiling Chlorination Reverse osmosis Sand filtration

Reverse osmosis

In BOD testing, why is dilution of the sample often required? To improve nutrient balance To prevent oxygen supersaturation To avoid complete oxygen depletion To accelerate oxidation

To avoid complete oxygen depletion

Which reagent is used in the standard COD test? Ferric chloride Sodium hydroxide Potassium dichromate Calcium carbonate

Potassium dichromate

If BOD is greater than COD, it indicates: Presence of heavy metals Non-biodegradable pollution Error in measurement Presence of toxic substances

Error in measurement

Which sector contributes the most to global carbon emissions? Agriculture Transportation Energy production Waste management

Energy production

What is the main source of carbon footprint in cement production? Fuel combustion Transportation Chemical decomposition of limestone Electricity consumption

Chemical decomposition of limestone

Which sector is classified under Scope 3 emissions? Purchased steam Company-owned vehicles Emissions from upstream transportation On-site combustion

Emissions from upstream transportation

Which statement about Scope 2 emissions is true? They are under direct operational control They result from outsourced production They arise from purchased energy They relate to product use phase

They arise from purchased energy

Emissions from leased buildings are typically categorized under: Scope 1 Scope 2 Scope 3 Not reported

Scope 3

Carbon trading is a method to: Encourage deforestation Limit individual travel Cap emissions and create economic incentives for reduction Exchange fossil fuels

Cap emissions and create economic incentives for reduction

The Clean Development Mechanism (CDM) allows: Developing countries to bypass climate rules Transfer of emissions to oceans Developed countries to invest in emission-reducing projects in developing countries Free trade of fossil fuels

Developed countries to invest in emission-reducing projects in developing countries

A carbon offset refers to: Reduction in carbon tax Certificate of energy savings Investment in projects that reduce or capture emissions Bonus credits from regulatory agencies

Investment in projects that reduce or capture emissions

The term “cradle-to-gate” in carbon accounting refers to: Emissions during use phase only Emissions from disposal Emissions from raw material extraction to factory gate Emissions during transport

Emissions from raw material extraction to factory gate

Photochemical smog is typically formed in: Forested areas Coastal regions Urban centers under high sunlight Areas with low wind speed and low temperature

Urban centers under high sunlight

What is the primary environmental concern with hydrofluorocarbons (HFCs)? Water pollution Toxicity to plants High global warming potential Ozone layer depletion

High global warming potential

Which of the following best defines "environmental impact assessment" (EIA)? A process for measuring the environmental impact of climate change A tool for regulating the extraction of natural resources A procedure for evaluating the potential environmental consequences of a proposed project or development A method for designing renewable energy systems

A procedure for evaluating the potential environmental consequences of a proposed project or development

Also known as the “Toxic and Hazardous Waste Management Act of 1990”. RA 8749 PD 1152 RA 6969 PD 1151

RA 6969

For protection of aquatic life in a fresh-water stream, sewage effluent should never lower the dissolved oxygen content lower than 1 ppm 10 ppm 5 ppm 20 ppm

5 ppm

Which of the following is a climate change mitigation strategy? Building seawalls to protect against rising sea levels Developing drought-resistant crops Switching from coal-fired to solar power generation Relocating coastal communities inland

Switching from coal-fired to solar power generation

Which ISO standard is associated with environmental management systems? ISO 50001 ISO 31000 ISO 14001 ISO 9001

ISO 14001

These materials have a large number of non-localized electrons, as an effect are very good conductors of electricity and heat. They are strong yet deformable, and extensively used in structural applications. Polymers Ceramics Metals Composites

Metals

What refers to the property of a substance to be repelled by a magnet due to the presence of paired electrons? Paramagnetic Ferromagnetic Diamagnetic Ferrimagnetic

Diamagnetic

Which of the following is true about refractory metals? Resistant to oxidation Resistant to corrosion Resistant to heat Resistant to sun’s rays

Resistant to heat

This refers to lowering the temperature of a liquid below its melting point before it becomes solid. Sub cooling Supercritical Super cooling Subcritical

Super cooling

The process where a physical mixture of carbide and powdered metal is heated in order to solidify the powder into single piece. Vitrification Ceramication Sintering Polymerization

Sintering

______ refers to the strong primary chemical bonds which forms some of the polymeric materials. Polymerization Vulcanization Cross – linking Copolymerization

Cross – linking

Polymers are materials that are found on Group 1 – 5 Group 3 – 12 Group 4B Group 1A

Group 4B

A composite material composed of large ceramic particles distributed over a ceramic binder, used chiefly in structural applications. cement nanofiber concrete fiberglass

concrete

What refers to the reciprocal dispersion of optical materials? Nusselt number Prandtl number Abbe number Schmidt number

Abbe number

It is a type of bond where relatively large interatomic forces are created by the sharing of electrons to form a bond with localized directional atoms. It is called the _____ bond. Ionic Metallic Covalent Secondary

Covalent

What is the bond angle of water? 109.5 degrees 110 degrees 105 degrees 107.5 degrees

105 degrees

Materials with binding energy in the range of 150 – 370 kcal/mol are considered to exhibit what type of bonding? Ionic Metallic Covalent Secondary

Covalent

This refers to a crystal system with unequal axes with all angles at right angle Tetragonal Rhombohedral Orthorhombic Hexagonal

Orthorhombic

The element beryllium has what crystal structure? FCC BCC HCP CCP

HCP

A grain boundary in a metal affect: Optical properties The crystal lattice constant Mechanical strength and electrical conductivity The chemical formula

Mechanical strength and electrical conductivity

Young’s modulus is a measure of: Ductility Hardness Elastic stiffness Plastic deformation

Elastic stiffness

Which property is most often improved by adding fibers to a composite? Density Ductility Toughness and tensile strength Electrical conductivity

Toughness and tensile strength

Heat treatment processes like annealing and quenching are used to: Change color of metals Increase electrical resistance Modify mechanical properties like hardness and ductility Remove rust

Modify mechanical properties like hardness and ductility

Which of the following metals typically crystallizes in a Face- Centered Cubic (FCC) structure? Chromium Iron (α-Fe) Aluminum Tungsten

Aluminum

A vacancy is a type of: Line defect Volume defect Point defect Grain boundary

Point defect

The ability of a material to withstand plastic deformation before fracture is: Stiffness Toughness Ductility Hardness

Ductility

Which of the following is considered a point defect in crystals Edge dislocation Twin boundary Vacancy Grain boundary

Vacancy

The elastic region in a stress-strain curve is defined by: Plastic flow Necking Linear increase in stress Fracture

Linear increase in stress

Which of the following fuels has the highest energy content per unit mass? Coal Hydrogen c. Wood d. Diesel

Hydrogen

Which of the following best explains why hydrogen fuel cells are considered environmentally friendly? Hydrogen is abundant in nature They release only water as a byproduct Hydrogen has a high energy density They require no external energy to operate

They release only water as a byproduct

Which of the following is an example of an endothermic reaction? Freezing of water Photosynthesis c. Combustion of methane d. Condensation of steam

Photosynthesis

Which of the following best describes an exergonic reaction? ΔG > 0 ΔG < 0 c. ΔH < 0 d. ΔS < 0

ΔG < 0

What happens to the entropy of the surroundings when an endothermic reaction occurs at constant pressure? It increases It decreases It remains unchanged It depends on the initial entropy

It decreases

The chemical potential of a component in a real gas mixture is defined using: Its mole fraction Its fugacity c. Its entropy d. Its partial pressure

Its fugacity

For the combustion of ethylene (C2H4)C2H4 (g) + O2 (g) → CO2 (g) + H2O (g)ΔHf0 (CO2) = -393.5 kJ/mol ΔHf0 (H2O) = -241.8 kJ/mol ΔHf0 (C2H4) = 52.3 kJ/mol -1560 kJ -1323 kJ c. -1411 kJ d. -1773 kJ

-1323 kJ

Which industrial process consumes the most energy globally? Steel production Aluminum refining c. Ammonia synthesis d. Cement manufacturing

Aluminum refining

What is the typical efficiency of a coal-fired power plant? 10-20% 30-40% c. 50-60% d. 80-90%

30-40%

What is the air fuel volume ratio when methane is burned with ideal air? 0.0840277777777778 9.52:1 c. 4.76:1 d. 5:1

9.52:1

Syngas is a mixture of: Hydrogen and methane Carbon monoxide and hydrogen Methane and oxygen Carbon dioxide and nitrogen

Carbon monoxide and hydrogen

What is the main component of biodiesel? Hydrocarbons Fatty acid methyl esters (FAME) Ethanol Methane

Fatty acid methyl esters (FAME)

Which section of an SDS provides guidance on safe handling and storage? Section 6 Section 7 c. Section 10 d. Section 14

Section 7

What is the primary purpose of SDS Section 16? To provide disposal guidelines To summarize key information, including preparation date and modifications To list toxicity data To provide handling precautions

To summarize key information, including preparation date and modifications

Which type of chemical reaction is a major concern in SDS Section 10 (Stability and Reactivity)? Precipitation Polymerization c. Neutralization d. Esterification

Polymerization

Which of the following is a common indicator of chemical instability? High boiling point Violent decomposition when heated Low molecular weight Odorless nature

Violent decomposition when heated

Which chemical should NEVER be stored in a glass container? Sulfuric acid Hydrofluoric acid c. Acetic acid d. Ammonia solution

Hydrofluoric acid

A student is heating an unknown compound, and a green flame appears. What element is likely present? Sodium Copper c. Potassium d. Sulfur

Copper

What is the main hazard of handling anhydrous ammonia? Highly explosive Severe frostbite and respiratory hazard Highly radioactive Low toxicity and stable at all conditions

Severe frostbite and respiratory hazard

Which of the following describes a pyrophoric substance? Reacts violently with acids Spontaneously ignites in air Decomposes at room temperature Dissolves metals quickly

Spontaneously ignites in air

A chemical with an NFPA health rating of 4 means: Slightly hazardous Severe health hazard c. Moderate hazard d. No significant health risk

Severe health hazard

How many sections are included in a standard Safety Data Sheet (SDS) according to the Globally Harmonized System (GHS)? a. 8 b. 16 c. 12 d. 20

b. 16

A gas mixture contains 3 moles of O2 and 2 moles of N2 in a 10 L container at 27°C. What is the partial pressure of O₂ in the mixture? 2.46 atm 7.38 atm c. 4.92 atm d. 6.15 atm

7.38 atm

If the compressibility factor (Z) > 1 for a gas, what does this indicate about the gas behavior? The gas behaves exactly like an ideal gas. The gas experiences more repulsive forces and occupies a larger volume than an ideal gas. The gas experiences strong attractive forces and compresses more than an ideal gas. The gas liquefies immediately.

The gas experiences more repulsive forces and occupies a larger volume than an ideal gas.

When a system is at equilibrium, what is the value of Gibbs free energy? Maximum Minimum c. Zero d. Undefined

Minimum

Given the following reactions and their enthalpy changes: C + O₂ → CO₂ ΔH = -393.5 kJ/mol CO + ½ O₂ → CO₂ ΔH = -283.0 kJ/mol 2C + O₂ → 2CO ΔH = -221.0 kJ/mol What is the enthalpy of formation of CO in kJ/mol? -283.0 kJ/mol -110.5 kJ/mol c. +110.5 kJ/mol d. +283.0 kJ/mol

-110.5 kJ/mol

Which thermodynamic property does the Clausius-Clapeyron equation relate to the slope of the vapor pressure curve? Temperature Entropy change of vaporization Pressure Volume change during phase transition

Entropy change of vaporization

For the reaction: 2A = 3BIf the chemical potential of A is 15 J/mol, what is the corresponding change in the chemical potential of B assuming equilibrium conditions? 10 J/mol -10 J/mol c. 22.5 J/mol d. -22.5 J/mol

-10 J/mol

What process occurs at the anode during an electrochemical reaction? Reduction Oxidation c. Electrodeposition d. Neutralization

Oxidation

Which colligative property explains why adding salt to ice lowers its melting point, causing roads to remain unfrozen in winter? Boiling point elevation Freezing point depression Osmotic pressure Vapor pressure lowering

Freezing point depression

If ΔG is positive, what does it indicate about a reaction? It is at equilibrium. It is non-spontaneous. c. It is spontaneous. d. It releases energy.

It is non-spontaneous.

A back titration is performed using potassium dichromate (K2Cr2O7). If 50.0 mL of a 0.100 M solution is used in the reaction, how many moles of Cr2O72- are present? 0.00250 moles 0.00500 moles c. 0.0100 moles d. 0.0500 moles

0.00500 moles

During the titration of a weak acid with a strong base, the pH rises from 3.0 to 4.7. What primarily causes this increase in pH? The complete neutralization of the weak acid The formation of its conjugate base, which partially resists further pH changes The rapid dissociation of water molecules The presence of excess strong base in the solution

The formation of its conjugate base, which partially resists further pH changes

Which law describes the relationship between absorbance and concentration in spectrophotometry? Boyle’s Law Beer-Lambert Law c. Henry’s Law d. Dalton’s Law

Beer-Lambert Law

In gravimetric analysis, coprecipitation occurs when: The desired analyte is fully precipitated without impurities An impurity is trapped within the precipitate structure The precipitate does not form at all The analyte is lost due to excessive heating

An impurity is trapped within the precipitate structure

In a complexometric titration, which reagent is commonly used to determine the hardness of water? Potassium permanganate Ethylenediaminetetraacetic acid Silver nitrate Sodium hydroxide

Ethylenediaminetetraacetic acid

What is the ratio of stress to strain in a material known as? Toughness Modulus of elasticity c. Plasticity d. Shear strength

Modulus of elasticity

What is the ratio of shear stress to shear strain called? Young’s modulus Shear modulus c. Bulk modulus d. Poisson’s ratio

Shear modulus

What property of a material does a higher modulus of elasticity indicate? The material is more flexible. The material is more brittle and rigid. The material absorbs more energy before breaking. The material has a higher thermal expansion.

The material is more brittle and rigid.

The modulus of elasticity is highest in which type of material? Polymers Ceramics c. Metals d. Rubber

Ceramics

Which of the following best defines elastomers? Polymers that permanently deform when stretched Polymers with high flexibility that return to their original shape after deformation Rigid polymers used in structural applications Thermoplastics that soften when heated and harden when cooled

Polymers with high flexibility that return to their original shape after deformation

At which point on a stress-strain curve can the yield strength be found? The point where stress reaches its maximum before failure The point where the material permanently deforms after elastic behavior The point where the material fractures The point where stress is directly proportional to strain

The point where the material permanently deforms after elastic behavior

What is the primary purpose of adding carbon to iron in steel production? To increase hardness and strength To improve corrosion resistance To make the steel more ductile To reduce the melting point significantly

To improve corrosion resistance

Why is cast iron preferred over steel in the construction of chemical reactor vessels in certain applications? better moldability higher corrosion resistance higher tensional strength higher ductility

higher corrosion resistance

What type of materials typically shows a decrease in resistivity as temperature increases? Metals Semiconductors Insulators Superconductors above critical temperature

Semiconductors

Which gas is predicted to be the most dangerous to human health and the environment in the next 100 years? Carbon dioxide Nitrogen oxides c. Methane d. Sulfur hexafluoride

Nitrogen oxides

What is the Philippines' total greenhouse gas (GHG) reduction target by 2030 under its Nationally Determined Contribution (NDC)? 100% reduction (Unconditional: 50%, Conditional: 50%) 75% reduction (Unconditional: 2.71%, Conditional: 72.29%) 50% reduction (Unconditional: 25%, Conditional: 25%) 25% reduction (Unconditional: 5%, Conditional: 20%)

75% reduction (Unconditional: 2.71%, Conditional: 72.29%)

Which of the following is an example of a Scope 1 greenhouse gas (GHG) emission? Emissions from electricity purchased from the grid Methane emissions from a landfill owned by a company CO₂ emissions from commuting employees' personal vehicles Carbon footprint from raw materials used in production

Methane emissions from a landfill owned by a company

In the context of Extended Producer Responsibility (EPR) laws, what does "take-back" mean? Consumers must return products to manufacturers for repair Producers are responsible for collecting and managing the disposal of their products after consumer use Retailers must store used products before disposal Government agencies must handle all waste collection and recycling

Producers are responsible for collecting and managing the disposal of their products after consumer use

Which property of wastewater is crucial for determining its ability to support aquatic life and indicates the level of organic pollution? Chemical oxygen demand Dissolved oxygen Total suspended solids Turbidity

Dissolved oxygen

A water treatment tank has a volume of 48,000 liters, and the flow rate of water entering the tank is 12,000 liters per hour. What is the retention time in hours? 2 hours 4 hours c. 3 hours d. 6 hours

4 hours

Give the mass empirical formula of the following compound if a sample contains 57.8%C, 36%H, and 38.6%O by mass. C2HO C4H3O2 C8H6O4 C12H9O6

C4H3O2

A 1.038 M sucrose in water solution has a density of 1.1 g/mL. Calculate the molality of the solution. 1.22 1.39 1.3 1.48

1.39

Vitamin A has a molar mass of 286.4 g/mol and a general molecular formula of CxHyE, where E is an unknown element. If vitamin A is 83.86% C and 10.56% H by mass, what is the molecular formula of vitamin A? C18H38O2 C20H30O C22H6O C20H15O2

C20H30O

In the compound KMnO4, what is the oxidation number of Mn? 6 7 4 3

If common salt NaCl is dissolved in water, which of the following statements is true about the behavior of the solution relative to the behavior of pure water? boiling point is lowered freezing point is decreased melting point increases none of this is true

freezing point is decreased

Which of the following is a homogeneous mixture? I. Water II. Water and alcohol III. Air I, II, and III II and III only I and II only I and III only

II and III only

It is defined as the tendency of an atom to attract electrons ionization energy electronegativity electron affinity activation energy

electronegativity

One angstrom equals to m 45726 45940 45910 46001

45940

Bonding between carbon atoms are electrovalent and strong covalent and strong electrovalent and weak covalent and weak

covalent and strong

Chromium III in water has what color? yellow violet blue green

violet

In which of the following molecule do we find bond angles of 109.5°? BF3 CCl4 SF4 NH3

CCl4

If you had a mole of U.S. dollar bills and equally distributed the money to all of the people of the world, how rich would every person be? Assume a world population of 7 billion. 76 trillion dollars 90 trillion dollars 42 trillion dollars 25 trillion dollars

90 trillion dollars

It is a high speed electrons emitted by an unstable nucleus alpha rays beta rays gamma rays UV rays

beta rays

The mass of a nucleus is less than the total mass of its nucleus. This fact indicates that some of the mass has been converted to radioactivity binding energy photoelectric effect thermal energy

binding energy

Match the radioactive isotope with its proper use: Tritium Heart scan in exercise Measure water content of body Kidney scan Cancer therapy

Measure water content of body

If one millieCurie is equal to 3.7 disintegrations/second and the intensity of any radiation decreases with the square of the distance from the source (I1/I2 = d22/d12, calculate the intensity of radiation at the distance of two meters when the intensity of radiation is 29 millicurie at a one meter distance. 16 mCi 7 mCi 8 mci 4 mCi

7 mCi

The heating value of a fuel depends primarily on: The ash content of the fuel The bond energies of the chemical components The molecular weight of the fuel The presence of oxygen

The bond energies of the chemical components

How does alpha, beta and gamma particle affect the mass number of an atom? 4, 0, 0 4,-1, 0 4, 1, 0 2,-1, 0

4,-1, 0

Polytetrafluoroethylene (PTFE) is commonly known as: Nylon Teflon Bakelite Kevlar

Teflon

Which process is used to increase the octane rating of gasoline? Thermal cracking Catalytic reforming Gasification Polymerization

Catalytic reforming

A radioactive isotope with an intensity (activity) of 100 mCi per vial is delivered to a hospital. The vial contains 10 mL of liquid. The instruction is to administer 2.5 mCi intravenously. How many milliliters of the liquid should be administered? 0.18 ml 0.25 ml 0.66 ml 0.40 ml

0.25 ml

Brass is an alloy of: Copper and tin Copper and zinc Aluminum and magnesium Iron and carbon

Copper and zinc

Which process is used to harden steel by rapid cooling? Annealing Quenching Polypropylene Polystyrene

Quenching

For each of the following, identify the radiation emitted. (1) Beryllium-10 changes to boron-10 (2) Europium-151m changes to europium-151 (3) Thallium-195 changes to mercury-195 (4) Plutonium-239 changes to uranium-235. beta, gamma, alpha, positron beta, gamma, positron, alpha alpha, gamma, positron, beta alpha, gamma, beta, positron

beta, gamma, positron, alpha

Which among the following has the highest boiling point? 1.0% soln. of (NH2)2CO 1.0% soln. of NaCl 1.0% soln. of C6H12O6 1.0% soln. of ZnSO4

1.0% soln. of NaCl

What is the main source of mercury contamination in aquatic ecosystems? Volcanic eruptions Coal-fired power plants Agriculture Forest fires

Coal-fired power plants

Which of the following represents a chemical property of matter? An iron nail attracted to a magnet A piece of paper spontaneously ignites when its temperature reaches 451 °F A block of wood floats on water A slab of marble feels cool to the touch

A piece of paper spontaneously ignites when its temperature reaches 451 °F

When light of sufficient energy shines on a metal, electrons are knocked off the surface of the metal. What is this phenomenon called? Electron harvesting Photoelectric effect Blackbody radiation Illumination

Photoelectric effect

The photoelectric effect equation: hv= phi + (1/2)mev2 is derived from which law? Law of conservation of charge Law of conservation of energy Law of conservation of mass Law of conservation of momentum

Law of conservation of energy

What type of orbital is designated by the quantum numbers (5, 1, 0, ± ½)? A 4s orbital A 5p orbital A 5s orbital A 5d orbital

A 5p orbital

Which of the following atoms has the lowest first ionization energy? Sr Cs S F

When benzoic acid dissolves in water, it partially reacts with water and ionizes to form benzoate and hydronium ions. In this reaction, what is the conjugate acid? Benzoate ions Hydronium ions Water Benzoic acid

Hydronium ions

When a can of soda is opened and CO2 is released to the atmosphere, what is the resultant pH of the soda? Decreases Increases The same All these

Increases

Buffer capacity is maximum when: pH = 0.5pKa pH = pKa pH = 2pKa pH = 0.1pKa

pH = pKa

Back titration is used when: There is no need for an indicator The analyte does not react directly with the titrant The titrant is volatile The reaction is too slow to reach an endpoint

The analyte does not react directly with the titrant

An ideal gas will only be considered in the following operating parameters: High Temperature, High Pressure High Temperature, Low Pressure Low Temperature, High Pressure Low Temperature, Low Pressure

High Temperature, Low Pressure

Which of the following is false regarding absolute zero? All molecules will stop moving Absolute zero can be achieved Temperature is 0 K Temperature is 0 R

Absolute zero can be achieved

Which of the following is false with KMT? Gas molecules move in random motion Due to collision of gas molecules with each other, some kinetic energy is lost The temperature of the whole system does not change with time The size of the molecules is negligible

Due to collision of gas molecules with each other, some kinetic energy is lost

The internal energy of an ideal gas depends on: Volume Absolute temperature Pressure Number of moles

Absolute temperature

Heat required to raise the temperature of 1 lbm of water by 1 ˚F. Calorie BTU Specific heat Heat capacity

BTU

Which of the following statements is/are true? (1) The criterion of equilibrium at constant temperature and pressure is dG = 0. (2) For a reversible process, dS = dQ / T. 1 only Both 1 and 2 2 only None of the above

Both 1 and 2

It is the property of a fluid that is caused by shearing effect of a fluid layer moving past another layer. Density Viscosity Flow Compressibility

Viscosity

For miscible systems, the boiling point of the solution is: Lower than the boiling point of the liquid with the lower boiling point Between the boiling points of the two liquids Above the boiling point of the liquid with the higher boiling point Cannot be determined

Between the boiling points of the two liquids

Determine which of the following occurrences tells us what happens when Le Chatelier’s principle is applied whether these are TRUE or FALSE. A.) The addition of a component causes the equilibrium to shift to the opposite side B.) The removal of the component causes the equilibrium to the side from which the component is removed. C.) Increasing the temperature drives an exothermic equilibrium to the side of the reactants, an endothermic equilibrium to the side of the product. D.) The addition of a catalyst has NO effect on the position of the equilibrium A.T;F;T;F T;T;T;T C.F;T;F;T D.F;F;F;F

T;T;T;T

Consider the exothermic reaction of sulfur dioxide and oxygen gas forming sulfur trioxide gas. Which of the following stresses will affect the equilibrium reaction to shift to the product side? sulfur trioxide is added to the system the reaction mixture is cooled the reaction mixture is heated depressurizing the system

the reaction mixture is cooled

What is the ratio of the most probable velocity to the RMS velocity to the average velocity of gases? 1:1.13:1.22 1:1.22:1.13 1:1.15:1.27 1:1.27:1.15

1:1.22:1.13

For the thermal properties based on the states of matter, which of the following is arranged in order of increasing thermal conductivity? solid < gas < liquid gas < liquid < solid liquid < gas < solid solid < liquid < gas

gas < liquid < solid

What is the normal state of naphthalene at 100°C? solid liquid gas plasma

liquid

Determine which particles are being described by each of the following statements: A. Has the greatest penetrative capability. B. Sometimes called as the positive electron. C. Contact with it can cause the greatest biological destruction. D. Cannot be affected by a magnetic field. Alpha Particles, Beta Particles, Gamma Rays, Positron Gamma Rays, Positron, Alpha Particles, Gamma Particles Beta Particles, Neutrino, Alpha Particles, Beta Particles Neutrino, Positron, Gamma Rays, Beta Particles

Gamma Rays, Positron, Alpha Particles, Gamma Particles

Which among the following scientists discovered radioactivity? Marie Curie Henri Becquerel Otto Hahn Ernest Rutherford

Henri Becquerel

The resistance of water to the passage of light through it is a measure of the color turbidity hardness dissolved gases

turbidity

It is the phenomenon that results in the overabundance of algae growth in bodies of water. It is also the natural process of nutrient enrichment that occurs over time in a body of water. biomagnification eutrophication anaerobic respiration thermal inversion

eutrophication

Hardness of water is usually expressed in parts per million of MgSO4 CaCO3 Na2CO3 CaCl2

CaCO3

Hard water can be softened by letting the calcium or magnesium ions settle out passing it through an ion exchanger chlorination filtration

passing it through an ion exchanger

It is the international salute that is currently the primary basis of the Philippines in its latest environmental dispute with Canada. Kyoto Protocol Basel Convention Copenhagen Talks Montreal Protocol

Basel Convention

Which of the acid combination is the dominant composition of acid rain? nitric acid and carbonic acid nitric acid and sulfuric acid carbonic acid and sulfuric acid none of the above

nitric acid and sulfuric acid

Which of the following is a common coagulant used in water treatment? Sodium hypochlorite Aluminum sulfate Activated carbon Ozone

Aluminum sulfate

Which of the following processes is used to remove phosphorus from wastewater? biological denitrification chemical precipitation with alum or ferric chloride membrane filtration adsorption onto activated carbon

chemical precipitation with alum or ferric chloride

What is the purpose of aeration in water treatment? Removal of pathogens Oxidation of iron and manganese Reduction of temperature Decreasing pH

Oxidation of iron and manganese

What is the primary advantage of using ozone for water disinfection? It produces no byproducts It is more effective than chlorine against viruses It has a longer residual effect than chlorine It is the cheapest method available

It is more effective than chlorine against viruses

What is the primary advantage of using anaerobic digestion in wastewater treatment? It produces a high-quality effluent for drinking water It reduces the volume of sludge generated and produces biogas It is cheaper than aerobic processes It increases the dissolved oxygen levels in the effluent

It reduces the volume of sludge generated and produces biogas

The final stage of wastewater treatment often involves: sedimentation disinfection coagulation aeration

disinfection

The biochemical oxygen demand (BOD) of a water sample measure: Total dissolved solids Organic pollutants Heavy metal contamination Nutrient levels

Organic pollutants

COD is preferred over BOD when: High accuracy is needed Time constraints exist Organic matter is highly biodegradable Wastewater is free of chemicals

Time constraints exist

The term "carbon footprint" refers to: Carbon dioxide emissions only All greenhouse gas emissions in CO₂ equivalent Only industrial emissions The weight of carbon in a fuel sample

All greenhouse gas emissions in CO₂ equivalent

Which gas is excluded when calculating carbon dioxide equivalent (CO₂e)? CH₄ O₃ N₂O CO₂

O₃

Carbon intensity refers to: Energy per unit mass CO₂ emitted per unit energy produced Fuel weight per km traveled Thermal conductivity of carbon

CO₂ emitted per unit energy produced

Which of the following environmental issues is most directly linked to the increase in CO₂ concentration in the atmosphere? Ozone layer depletion Ocean acidification Loss of biodiversity Desertification

Ocean acidification

The most significant source of anthropogenic methane is: Volcanoes Landfills Lightning Ocean currents

Landfills

The GHG Protocol divides emissions into how many Scopes? a. 2 b. 3 4 5

b. 3

A carbon tax is intended to: Fund oil exploration Encourage emissions reduction through market pressure Promote natural gas Replace income tax

Encourage emissions reduction through market pressure

What is a typical emission factor used for calculating CO₂ from diesel combustion? 0.5 kg CO₂/L 2.68 kg CO₂/L 4.2 kg CO₂/L 7.9 kg CO₂/L

2.68 kg CO₂/L

What is the primary reaction mechanism behind the formation of tropospheric ozone? CO₂ reacting with water vapor VOCs and NOx reacting under sunlight SO₂ and NO₂ condensation Methane combustion

VOCs and NOx reacting under sunlight

Afforestation helps mitigate climate change by: Increasing fossil fuel reserves Enhancing carbon sequestration Decreasing oxygen levels Increasing albedo

Enhancing carbon sequestration

What is the primary goal of carbon capture and storage (CCS)? Reduce air pollution Remove carbon dioxide from the atmosphere Improve energy efficiency Increase fossil fuel production

Remove carbon dioxide from the atmosphere

Which protocol was established to reduce greenhouse gas emissions? Montreal Protocol Kyoto Protocol Basel Convention Stockholm Convention

Kyoto Protocol

Which of the following gases is not included in the Kyoto Protocol’s “basket of six” GHGs? CO₂ NH₃ CH₄ SF₆

NH₃

What is the goal of the Paris Agreement? Eliminate fossil fuel usage Keep global warming below 2°C Reduce ozone depletion Promote nuclear energy

Keep global warming below 2°C

Which of the following best describes "extended producer responsibility" (EPR)? Regulations that force consumers to reduce waste A program that encourages producers to take responsibility for the entire lifecycle of their products, including disposal Requirements for government agencies to manage waste disposal A law that mandates waste recycling only in urban areas

A program that encourages producers to take responsibility for the entire lifecycle of their products, including disposal

Which of the following best describes carbon footprint? The amount of oxygen consumed by an individual or activity The total amount of greenhouse gases emitted directly or indirectly by a person, organization, or product The measure of air pollution from sulfur compounds The amount of energy used per capita in a given area

The total amount of greenhouse gases emitted directly or indirectly by a person, organization, or product

Permanent hardness of water is due to the presence of calcium bicarbonate sulfates and chlorides of calcium and magnesium nitrates of Na and K sulfates and chlorides of sodium and potassium

sulfates and chlorides of calcium and magnesium

Scope 1 emissions are defined as: Indirect emissions from purchased electricity, heat, or steam Direct GHG emissions from sources that are owned or controlled by the organization Emissions resulting from employee commuting and business travel Emissions from the production of purchased materials and fuels

Direct GHG emissions from sources that are owned or controlled by the organization

Which of the following is a Scope 2 emission source? Fugitive emissions from cooling systems Electricity purchased from the grid Fuel combustion in company-owned vehicles Process emissions from chemical reactions

Electricity purchased from the grid

In the context of climate policy, what does the term “net zero” imply? A state where no greenhouse gases are emitted A state where GHG emissions are equal to GHG removals A situation where fossil fuel use is banned Zero emissions from electricity generation only

A state where GHG emissions are equal to GHG removals

Scope 3 emissions in carbon accounting refer to: Direct emissions from owned equipment Emissions from the value chain, including suppliers and customers Emissions from renewable energy Indirect emissions from purchased electricity

Emissions from the value chain, including suppliers and customers

What are the main or fundamental classes of engineering materials? Composite materials and noncomposite materials Metallic materials, polymeric materials and ceramic materials Metallic materials, nonmetallic materials, polymeric materials and ceramic materials Metallic materials and nonmetallic materials

Metallic materials, polymeric materials and ceramic materials

Which of the following metals has the highest electrical conductivity? Zinc Copper Gold Aluminum

Copper

What type of materials behaves like iron when placed in a magnetic field? Crystals Ferromagnetic Amorphous Metalloids

Ferromagnetic

This element is used in modern, super strong permanent magnets because of their high coercivities beryllium neodymium yttrium alnico

neodymium

_______ materials are approximately considered to be those having a fracture strain of less than about 5%. Ceramic Brittle Ductile Malleable

Brittle

Polymer comes from Greek words poly which means many and meros which means metal part material plastic

part

Which of the following plastics does not burn but rather extinguishes itself? polyester nylon acrylic propylene

nylon

The movement of liquid through a phosphor diaphragm of other permeable solid as a result of an applied electric field. Electrophoresis Electron osmosis Electrical diffusion All of these are correct

Electron osmosis

Changes of state from where particles are able to move freely to a state where they can no longer move freely and can only vibrate. Melting Freezing Evaporation Condensation

Freezing

It refers to sharing of delocalized electron to form strong bond between atoms. It is called the ____ bond. Ionic Metallic Covalent Secondary

Metallic

An elemental solid having a different crystal structure, usually due to the prevailing temperature and pressure. Crystal Allotrope Polycrystal Amorphous

Allotrope

What is the atomic packing factor of simple cubic (SC) crystal structure? 0.68 0.52 0.74 0.93

0.52

Which class of materials generally exhibits high strength, high stiffness, but is brittle? Polymers Ceramics Metals Composites

Ceramics

Body-Centered Cubic (BCC) structures are generally: Ductile and dense Brittle at low temperatures Only found in non-metals Poor thermal conductors

Brittle at low temperatures

The ability of a material to return to its original shape after deformation is called: Plasticity Elasticity Malleability Hardness

Elasticity

The atomic packing factor (APF) of a BCC structure is approximately: 0.52 0.68 0.74 1

0.68

The number of nearest neighbor atoms in a BCC unit cell is: 6 8 12 14

The crystallographic direction [111] in a cubic lattice refers to: A direction parallel to the x-axis only A diagonal across the cube The direction along the face of the cube The direction with the lowest atomic density

A diagonal across the cube

Which type of bonding is dominant in ceramics? Hydrogen bonding Ionic and covalent Van der Waals Metallic

Ionic and covalent

A thermoplastic polymer is characterized by: Irreversible hardening when heated Ability to soften and be remolded multiple times Crystalline structure High thermal conductivity

Ability to soften and be remolded multiple times

Which of the following is a common ceramic processing technique? Annealing Sintering Extrusion Rolling

Sintering

A composite material is made to: Lower production cost Combine properties of multiple materials Minimize electrical resistance Reduce weight

Combine properties of multiple materials

Why is hydrogen not widely used as a fuel source despite its high energy density? It is highly explosive and difficult to store It is more expensive than gasoline It is not renewable It is heavier than air

It is highly explosive and difficult to store

What is the primary reason why metals conduct heat better than non- metals? They have free electrons They have stronger atomic bonds They have lower densities They have higher melting points

They have free electrons

A higher enthalpy of vaporization (ΔHvap) results in which of the following trends in the Clausius-Clapeyron plot? A steeper negative slope A shallower negative slope A linear increase in vapor pressure No change in slope

A steeper negative slope

The Helmholtz free energy is defined as: A=U−TS A=G−PV c. A=H−TS d. A=S−TQ

A=U−TS

The fugacity of a real gas at 2 atm is found to be 1.8 atm. What is the fugacity coefficient? 0.9 1.2 c. 1.1 d. 0.8

0.9

Which country currently produces the highest percentage of its electricity from nuclear energy? France China c. USA d. Germany

France

Why does cooking food at higher altitudes take longer? Water boils at a lower temperature Water boils at a higher temperature Air has higher humidity Heat transfer increases

Water boils at a lower temperature

The unit of energy in the SI system is: Joule Calorie c. Watt d. Pascal

Joule

Which type of reaction powers nuclear reactors? Fission Fusion c. Combustion d. Oxidation

Fission

Which section of an SDS describes disposal considerations? Section 13 Section 12 c. Section 11 d. Section 15

Section 13

Which section of an SDS lists the chemical name and CAS number? Section 1 Section 2 c. Section 3 d. Section 6

Section 1

Which chemical hazard classification is assigned to a substance that causes irreversible skin damage? Corrosive Irritant c. Flammable liquid d. Sensitizer

Corrosive

Which of the following conditions increases the risk of static discharge igniting flammable vapors? Low humidity High humidity c. High atmospheric pressure d. Large container size

Low humidity

What does LC50 indicate in toxicology? The concentration that kills 50% of test organisms The concentration where a chemical ignites The lowest concentration detected by odor The concentration at which an antidote is required

The concentration that kills 50% of test organisms

Which GHS hazard category is considered the most dangerous for acute toxicity? Category 1 Category 3 c. Category 5 d. Category 6

Category 1

What is the value of ΔG (Gibbs free energy change) when a system is at equilibrium? ΔG = 0 ΔG > 0 c. ΔG < 0 d. infinity

ΔG = 0

A liquid solution follows Raoult’s Law, where the pure vapor pressures of components A and B are: PA0 = 80 kPa and PB0 = 60 kPa. If the mole fraction of A in the liquid phase is 0.4, what is the total vapor pressure of the solution? 68 kPa 72 kPa c. 76 kPa d. 80 kPa

68 kPa

In thermodynamics, exergy refers to: Energy available for useful work Total energy in a system Heat capacity Internal energy

Energy available for useful work

If equal amounts of BaCl₂ and Na₂SO₄ solutions are mixed, what will be the precipitate formed? BaSO₄ BaCl₂ c. NaCl d. Na2SO4

BaSO₄

Which of the following represents the gravimetric factor used to convert the mass of a precipitate to the concentration of the analyte in a sample? Molar mass of precipitate / Molar mass of analyte 0.1 1 Mass of precipitate / Volume of analyte

Molar mass of precipitate / Molar mass of analyte

Which of the following best defines the equivalence point in a titration? The point where the amount of titrant added is stoichiometrically equal to the analyte in the solution The point where the color of the indicator changes The point where the pH reaches 7 The point where no more titrants can be added

The point where the amount of titrant added is stoichiometrically equal to the analyte in the solution

A sample solution is analyzed using a spectrophotometer. If the concentration of the solution is doubled, what will happen to its absorbance, assuming all other conditions remain constant? The absorbance will double. The absorbance will decrease by half. The absorbance will remain the same. The absorbance will increase four times.

The absorbance will double.

A solution with a molar absorptivity of 50 L/mol-cm has an absorbance of 1.0 in a 1 cm cuvette. What is the concentration of the solution? 0.02 M 0.05 M c. 0.10 M d. 1.00 M

0.02 M

Determine the absorbance of a liquid solution whose transmittance is 85%. 0.0706 0.9294 c. 0.1500 d. 0.1625

0.0706

In a redox titration using potassium permanganate, what is the role of MnO₄⁻? It acts as an oxidizing agent It acts as a reducing agent It stabilizes the pH of the solution It neutralizes the acid in the reaction

It acts as an oxidizing agent

What is the major factor that affects the rate of electron conduction in a material? The resistivity of the material The density of the material The atomic mass of the conductor The color of the material

The resistivity of the material

Which method is the most economical to produce aluminum matrix composites? Stir casting Powder metallurgy c. Tungsten infiltration d. Extrusion

Stir casting

How does the resistivity of a typical metal change with increasing temperature? It increases due to more frequent electron collisions. It decreases as the metal expands. It remains constant because resistivity is a material property. It fluctuates randomly with temperature changes.

It increases due to more frequent electron collisions.

What is the main function of Volatile Organic Compounds (VOCs) in air pollution? They react with nitrogen oxides (NOx) to form ground-level ozone and smog They directly contribute to global warming like CO₂ They absorb harmful UV radiation in the atmosphere They help in neutralizing acidic pollutants in the air

They react with nitrogen oxides (NOx) to form ground-level ozone and smog

Which gas is considered a “silent killer” due to its colorless, odorless nature and ability to cause suffocation? Carbon monoxide Ozone c. Sulfur dioxide d. Hydrogen sulfide

Carbon monoxide

What is the primary use of Greenhouse Gas (GHG) accounting? To measure and monitor greenhouse gas emissions To predict future climate changes To regulate air pollution levels To improve industrial efficiency

To measure and monitor greenhouse gas emissions

What is a carbon footprint in the context of GHG accounting? The total amount of greenhouse gases emitted directly or indirectly by an entity The number of trees planted to offset emissions The total weight of CO₂ in the atmosphere The amount of carbon stored in fossil fuels

The total amount of greenhouse gases emitted directly or indirectly by an entity

What is the standard framework used for corporate GHG accounting? Kyoto Protocol GHG Protocol Intergovernmental Panel on Climate Change (IPCC) Reports Environmental Impact Assessment (EIA)

Kyoto Protocol

Which of the following is required to calculate Scope 2 greenhouse gas (GHG) emissions? Electricity consumption and the emission factor of the electricity source Fuel combustion in company-owned vehicles Employee commuting and business travel data Industrial process emissions from chemical reactions

Electricity consumption and the emission factor of the electricity source

What is the primary purpose of the cold lime process in water treatment? To remove temporary and permanent hardness from water To disinfect water by killing bacteria To increase the solubility of calcium and magnesium salts To reduce the pH of water for industrial use

To remove temporary and permanent hardness from water

What is the primary purpose of an equalization pond in wastewater treatment? To balance flow rate and pollutant concentration before further treatment To remove suspended solids through sedimentation To disinfect wastewater by killing bacteria and viruses To completely remove organic matter before discharge

To balance flow rate and pollutant concentration before further treatment

What is the driving force in the reverse osmosis process? Pressure difference Gravity c. Concentration gradient d. Temperature difference

Pressure difference

A water treatment system uses an ion exchange resin to remove contaminants. The initial concentration of a pollutant is 800 ppm. The concentration decreases by half for every 2 cm of resin bed length. If the water passes through a 6 cm resin bed, what will be the final concentration of the pollutant? 100 ppm 400 ppm c. 200 ppm d. 800 ppm

100 ppm

Paint is what type of colloid? sol gel emulsion liquid foam

sol

German silver is an alloy of copper, nickel, and zinc silver, zinc, and aluminum copper, aluminum, and silver silver, nickel, and zinc

copper, nickel, and zinc

The boiling point of one mole of sugar in 1 liter of water is 100.52˚C 101.5˚C 100.78˚C 100˚C

100.52˚C

The solubility of BaSO4 in water is 0.00092 gram per 100 ml. Find the value of Ksp for BaSO4. 1.5x10-9 1.5x10-7 1.5x10-8 1.5x10-6

1.5x10-9

Wood alcohol is methanol grain alcohol ethanol 2-propanol

methanol

The differing abilities of substances to adhere to the surfaces of various solids such as paper and starch can also be used to separate mixtures. This is the basis of . chromatography filtration distillation extraction

chromatography

Transition elements are found in the d and f block s block p block d block

d and f block

Among the intermolecular forces of attraction, which one is present in CCl4? London Dispersion Forces hydrogen bonding dipole-dipole forces network covalent

London Dispersion Forces

A yellowish gas chlorine nitrogen carbon dioxide hydrogen

chlorine

A sample of carbon dioxide that undergoes transformation from solid to liquid to gas would undergo a change in density a change in mass a change in composition no change in physical properties

a change in density

From the thermal decomposition of a pure solid, we obtained a solid and a gas, each of which is a pure substance. From this information, we can conclude with certainty that the original solid is not an element at least one of the products is an element the solid is a compound and the gas is an element Both product are elements

the original solid is not an element

When concentrates sulfuric acid is diluted with water, the solution becomes warm, therefore the reaction is exothermic the reaction is endothermic the energy of the universe is increased the energy of both the system and the surroundings is decreased

the reaction is exothermic

The larger the numerical value of the bond energy, the Stronger the bond No relation to bond strength Weaker the bond None of these

Stronger the bond

In each case, tell whether the bond is ionic, polar covalent, or nonpolar covalent: Br2, BrCl, HCl, SrF2, SiH4, CO, N2, CsCl nonpolar covalent, nonpolar covalent, polar covalent, ionic, nonpolar covalent, polar covalent, nonpolar covalent, ionic polar covalent, ionic, polar covalent, nonpolar covalent, nonpolar covalent, nonpolar covalent, polar covalent, polar covalent nonpolar covalent, nonpolar covalent, ionic, nonpolar covalent, polar covalent, nonpolar covalent, ionic nonpolar covalent, polar covalent, nonpolar covalent, nonpolar covalent, polar covalent, polar covalent, ionic, polar covalent

nonpolar covalent, nonpolar covalent, polar covalent, ionic, nonpolar covalent, polar covalent, nonpolar covalent, ionic

Balance the chemical equation given K4Fe(CN)6 + H2SO4 + H2O = K2SO4 + FeSO4 + (NH4)2SO4 + CO 1,6,6,2,1,3,6 2,6,6,2,1,3,6 6,3,1,2,6,6,1 1,6,6,2,1,2,6

1,6,6,2,1,3,6

When U-235 is bombarded with one neutron, fission occurs and the products are three neutrons, Kr-94 and Ba-139 Ba-141 Ce-139 I-142

Ba-139

Positron is a particle with mass = 0 & charge = + 1 mass = 1 & charge = 0 mass = 0 & charge = 0 mass = 1 & charge = -1

mass = 0 & charge = + 1

Match the radioactive isotope with its proper use: Thallium-201 Heart scan in exercise Measure water content of body Kidney scan Cancer therapy

Heart scan in exercise

Tritium (3H) decays by beta emission to 3He with a half-life of 12.26 years. A sample of a tritiated compound has an initial activity of 0.833 Bq. Calculate the number Ni of tritium nuclei in the sample initially, the decay constant k, and the activity after 2.50 years. 4.7x108 nuclei, 1.8x10-9/s, 0.72 Bq 5.0x106 nuclei, 2.7x10-8/s, 0.84 Bq 3.2x108 nuclei, 1.5x10-9/s, 0.66 Bq 2.9x106 nuclei, 2.9x10-8/s, 0.93 Bq

4.7x108 nuclei, 1.8x10-9/s, 0.72 Bq

What is the mass of a 50 µCi sample of pure 131I? 4x10-10 g 1x10-9 g 3x10-7 g 2x10-12 g

4x10-10 g

The Gibbs free energy change (ΔG) of a spontaneous reaction at constant temperature and pressure is always: Negative Dependent on entropy change Zero Positive

Negative

A fuel cell operates based on the: Direct conversion of chemical energy into electrical energy Combustion of hydrocarbons Catalytic cracking of petroleum Chemical reaction between carbon dioxide and water

Direct conversion of chemical energy into electrical energy

Which metal is commonly added to steel to improve its corrosion resistance? Chromium Nickel Lead Copper

Chromium

The primary reason for using a fume hood when handling volatile chemicals is to: Protect the user from inhaling toxic vapors Improve chemical reactivity Reduce fire hazards Prevent contamination of the laboratory

Protect the user from inhaling toxic vapors

Which ceramic material is commonly used in high-temperature applications? Silicon carbide Polystyrene Copper oxide Polyethylene

Silicon carbide

Which of the following materials is an example of a thermosetting polymer? Epoxy resin Polypropylene Polyethylene Polystyrene

Epoxy resin

Which type of radiation is most commonly associated with nuclear waste disposal concerns? Gamma radiation Beta radiation Alpha radiation Infrared radiation

Gamma radiation

Who discovered that the atom is almost entirely composed of empty space? Ernest Rutherford J. J. Thomson R. A. Millikan Wilhelm Roentgen

Ernest Rutherford

The principle of gravimetric analysis relies on: Precipitation and weighing of a compound Titration with a known solution Measuring light absorption pH adjustments

Precipitation and weighing of a compound

The absorbance of a solution is directly proportional to: Concentration and path length Temperature and time Density and refractive index Surface area and volume

Concentration and path length

Which of the following is a key requirement for precipitation gravimetry? The precipitate should be pure and easily filtered The precipitate should be hygroscopic The precipitate should form rapidly The precipitate should be highly soluble

The precipitate should be pure and easily filtered

When gas molecules collide, they experience collision. Perfectly elastic Imperfect elastic Perfectly inelastic Imperfect inelastic

Perfectly elastic

A sample of an ideal gas has an internal energy of U and is then compressed to ½ of its original volume while the temperature stays the same. What is the new internal energy of the ideal gas in terms of U? U U/2 U/4 2U

If the entropy of a system decreases, the entropy of its surroundings Must always increase Must always decrease May increase or decrease Not enough information to answer the question

Must always increase

The amount of heat absorbed when CO2 gas reacts with a solid CaO to form solid CaCO3 is measured in a bomb calorimeter. The data obtained give a direct measure of: ΔU VΔP ΔH CP

ΔU

The equilibrium intensive state of a system is described by specifying the temperature, pressure, and: Mole fractions Number of moles Volume Chemical potential

Mole fractions

The fugacity of a real gas is equal to: The pressure of an ideal gas which has the same chemical potential as the real gas The pressure of a real gas which has the same chemical potential as the ideal gas The chemical potential of an ideal gas which has the same pressure as the real gas The chemical potential of a real gas which has the same pressure as the ideal gas

The pressure of an ideal gas which has the same chemical potential as the real gas

Which of the following does not have a zero enthalpy of formation at 298.15 K? Li(g) He(g) Hg(l) Br2(l)

Li(g)

State Le Chatelier’s Principle. Le Chatelier’s principle states that when a stress is placed on a system in equilibrium, the system tends to change in a way that relieves the stress. All of these Examples of the application of Le Chatelier’s principle are blowing your breath through a straw and dissolving alka seltzer tablet in a glass of water. Le Chatelier’s principle explains both the formation and decomposition of acids, where anything that might act to increase the concentration of an acid would produce an increase in the other components so as to keep the numerical

Le Chatelier’s principle states that when a stress is placed on a system in equilibrium, the system tends to change in a way that relieves the stress.

The coexistence curve where the plot of pressure versus temperature along which the two phases coexist was shown by Clausius-Clapeyron. What did Clausius postulate? The Clapeyron equation was simplified by assuming that the vapor obeys the ideal gas law and by neglecting the molar volume of the liquid VL in comparison with the molar volume of the gas VG The Clausius-Clapeyron equation does not apply to this situation The Clausius-Clapeyron theory is applicable only for vaporization and sublimation condition Both scientists apply their postulates to linear and curvilinear representation

The Clapeyron equation was simplified by assuming that the vapor obeys the ideal gas law and by neglecting the molar volume of the liquid VL in comparison with the molar volume of the gas VG

All colligative properties stem from the of the chemical potential of the liquid solvent as a result of the presence of the solute. Reduction Change Enlargement A or B or C, depending on the identities of the solute and solvent

Reduction

When a solute is introduced to a liquid system, the entropy of the said system: Increases Decreases Stays the same Can’t be determined

Increases

Among the following, which compound will produce the least lowering of the vapor pressure of a solution? sucrose, C12H22O11 Aluminum chloride, AlCl3 Table salt, NaCl Sodium sulfate, Na2SO4

sucrose, C12H22O11

Which of the following statements is true? Trouton’s rule fails for highly polar liquids It is impossible to go from vapor phase to liquid phase without condensation For C compounds and P phases, there are a total of CP intensive variables to be specified At high pressures, the latent heat of vaporization is a measure of the strength of the intermolecular forces of the liquid

Trouton’s rule fails for highly polar liquids

What is the significance of colligative property in physical chemistry? It refers to the freezing point depression, boiling point elevation, osmotic pressure and lowering of the vapor pressure by a nonvolatile solute It refers to the temperature, pressure and energy of fusion of volatile solutes in phase equilibrium It refers to the non-existence of pressure among molecules within the solute It refers to the temperature differentials exhibited by non-volatile solutes in reactions

It refers to the freezing point depression, boiling point elevation, osmotic pressure and lowering of the vapor pressure by a nonvolatile solute

Are galvanic cells and electrolytic cells the same? Why? No. because galvanic cells are electrochemical cells in which chemical reactions occur spontaneously; while in electrolytic cells, the chemical reaction is caused by an externally applied potential difference. No, because galvanic cells need a constant supply of electricity while electrolytic cells depend on intermittent source of power. Yes, because they are both electrochemical cells and their uses are common to each other Yes, because galvanic cells and electrolytic cells are both electrochemical cells.

No. because galvanic cells are electrochemical cells in which chemical reactions occur spontaneously; while in electrolytic cells, the chemical reaction is caused by an externally applied potential difference.

If the entropy of a system decreases, the entropy of its surroundings Must always increase Must always decrease May increase or decrease Not enough information to answer the question

Must always increase

For a criminal case, two men are interrogated in regards to an attempted poisoning of a police officer. During the investigation, it was found that both men had traces of Polonium- 210 on their hands while a third accomplice of theirs had Po-210 on his clothes. Through analysis of the police officers stomach content, it was confirmed that he had ingested Po-210. Which among them is/are bound to die if not properly treated? The police officer only The two men and the third accomplice The police officer and the two men All four of them

The police officer only

In which among the following can a Cherenkov Radiation be observed? In the water surrounding the core of a Nuclear Reactor In the Mushroom Cloud produced after a Hydrogen Bomb Explosion In a particle accelerator after the bombardment of two nuclides In the Sun’s Corona during a Solar Eclipse

In the water surrounding the core of a Nuclear Reactor

The total solids in water are due to the presence of suspended and dissolved solids suspended and floating solids colloidal and settleable solids colloidal and bacterial load

suspended and dissolved solids

In the determination of BOD, the reaction takes place at 200C 300C 400C 500C

200C

Involves the accumulation of trace metals through each species of the food chain. biomagnification denitrification anaerobic respiration eutrophication

biomagnification

A trace metal which causes Itai-itai diseases is cadmium silver mercury chromium

cadmium

Type of wastewater treatment that employs physical and chemical treatment methods to remove or reduce a high percentage of suspended solids and toxic materials. Primary Treatment Secondary Treatment Tertiary Treatment Minor Treatment

Primary Treatment

Process whereby coarse matter (suspended or floating) of a certain size can be strained out of flowing water with the aid of bars, fines wires or rocks. screening sedimentation flotation flocculation

screening

“Smokey Mountain” is a typical example of a facility for solid waste. It is classified as open dumping site sanitary landfill transfer station material recovery facility

open dumping site

It is an odorless and colorless gas that is lethal to humans with exposure as short as a few minutes to concentrations exceeding 5000 ppm. It reacts with hemoglobin in the blood rendering the latter incapable of carrying oxygen to the body. carbon monoxide hydrogen supplied sulfur dioxide sulfur trioxide

carbon monoxide

The main advantage of trickling filter over activated sludge is: lower power requirement higher BOD removal efficiency smaller footprint better pathogen removal

lower power requirement

The Air Quality Index (AQI) includes which of the following parameters? PM, NO₂, O₃, CO VOCs, UV, noise Temperature, wind speed, humidity Methane, ethane, propane

PM, NO₂, O₃, CO

Carbon sequestration refers to: Capturing and storing CO₂ Increasing carbon emissions Burning fossil fuels Recycling plastic waste

Capturing and storing CO₂

The primary environmental impact of urban sprawl is: Decreased air quality due to increased vehicle emissions Increased biodiversity in urban areas Improved access to green spaces Reduced energy consumption

Decreased air quality due to increased vehicle emissions

The sludge from wastewater treatment when subjected to anaerobic digestion produces a gas which can be used as fuel. This important gas is methane butane propane carbon monoxide

methane

Also known as the Philippine Clean Air Act of 1999 is RA 8749 RA 6969 RA 9003 RA 9297

RA 8749

Scrubbers are used to reduce sulfur emissions generated by burning of the coal to cleanse gas tank emissions in hybrid vehicles to cleanse PCB’s from farmed salmon to enhance the growth of wheat

to reduce sulfur emissions generated by burning of the coal

What did the Kyoto Protocol propose to regulate? the emission of greenhouse gases loss of biological habitats ozone depletion use of natural resources

the emission of greenhouse gases

What role do chlorofluorocarbons play in the environment? they lead to depletion of stratospheric ozone they add ozone to the stratosphere they lead to depletion of ground level ozone they add ozone to the troposphere

they lead to depletion of stratospheric ozone

Which of the following is not a refractory metal? Lead Niobium Tungsten Tantalum

Lead

What metal has the lowest boiling temperature? Mercury Iron Steel Molybdenum

Mercury

What are compounds of metallic and nonmetallic elements called? Ceramics Metalloids Semiconductor Alloys

Ceramics

Oxides, nitrides and carbides are main compositional classes of what type of material? ceramics metals composites polymers

ceramics

The process of gluing the powders together with glasses to form other ceramic materials. Vitrification Ceramication Sintering Polymerization

Vitrification

Ceramic materials are found on Group 1 – 5 Group 3 – 12 Group 4B Group 1A

Group 1 – 5

The term “blend” refers to materials that are mixture of two or more polymers metal and non – metal a polymeric and a ceramic two or more ceramic

two or more polymers

In polymers, what refers to a large molecule with alternating mers? Copolymer Monomer Cross – linking Vulcanization

Copolymer

The average number of mers in the molecule of a polymer is known as: Degree of polymerization Polymerization coefficient Copolymerization constant All of the choices are correct

Degree of polymerization

These are materials, commonly used as actuators, which after having been deformed revert back to their original shapes when temperature is changed. Shape memory alloys Piezoelectric materials Magnetorestrictive materials Electrorheological materials

Shape memory alloys

What is the strongest material? Carbon nanotubes Shape memory alloys Fullerenes Diamond

Carbon nanotubes

A device used in biotelemetry for monitoring the physiologic activity of an animal, such as pH values of stomach acid radio pill biotelemeter biomed pH meter

radio pill

In this type of bond, a relatively large interatomic force that tends to energy transfer from one atom to another that are bonded together by coulombic force. It is called the ________ bond. Ionic Metallic Covalent Secondary

Ionic

A material whose atomic arrangement occurs as periodic, repeating structures over large distances Crystalline Solid Polycrystalline Amorphous

Crystalline

It is the enthalpy change associated with the condensation of gaseous positive and negative ion into a crystal. Lattice energy Raoult’s Law Enthalpy energy Schottky defect

Lattice energy

This refers to distance between two nuclei of atoms. bond length bond radius bond distance All of these.

bond length

The arrangement of the atoms in a material into a regular repeatable pattern. Crystal structure Atomic structure Domain Lattice

Crystal structure

What is another name for face – centered cubic (fcc) crystal structure? Close Cubic Packed (CCP) Body Centered Cubic (BCC) Hexagonal Close Packed (HCP) Simple Cubic (SC)

Close Cubic Packed (CCP)

Calculate the volume of an FCC unit cell in terms of the atomic radius R. V = 16R3√4 V = 16R3√3 V = 4R3√4 V = 4R3√3

V = 16R3√4

What two crystal structures have the same coordination number? FCC and HCP BCC and CCP BCC and HCP CCP and FCC

FCC and HCP

What two crystal structures have the same atomic packing factor? FCC and HCP BCC and CCP BCC and HCP CCP and FCC

FCC and HCP

This refers to the number of atoms touching a particular atom, or the number of nearest neighbors of an atom. Coordination number Miller indices Atomic Packing Factor Bravais Structure

Coordination number

Which structure is most closely associated with close-packing and high ductility? Face-Centered Cubic (FCC) Hexagonal Closed Packed (HCP) Body-Centered Cubic (BCC) Amorphous structure

Face-Centered Cubic (FCC)

Which of the following statements about HCP (Hexagonal Close Packed) structures is correct? HCP has fewer slip systems than FCC, leading to lower ductility HCP metals are the most ductile metals HCP has the same packing efficiency as BCC HCP structures are amorphous in nature

HCP has fewer slip systems than FCC, leading to lower ductility

In crystallography, the interplanar spacing (d) for a cubic crystal system is inversely proportional to: Miller indices squared Atomic weight Atomic number Lattice strain

Miller indices squared

What type of crystal structure does gold (Au) possess? FCC HCP Amorphous BCC

FCC