Coaching Flashcards
(163 cards)
1
Q
Which of the following is the primary role of greenhouse gases (GHGs) in Earth’s atmosphere?
A
To trap heat and regulate the planet’s temperature
2
Q
Which greenhouse gas is primarily responsible for the enhanced greenhouse effect due to
human activities?
A
c.Carbon dioxide
3
Q
What is the key difference between gram-positive and gram-negative bacteria based on their cell wall structure?
A
Gram-positive bacteria have a thick peptidoglycan layer and no outer
membrane
gram-negative bacteria have a thin peptidoglycan layer and an outer membrane
4
Q
Which of the following is a key characteristic of the cell wall of gram-negative bacteria?
A
Presence of lipopolysaccharide
5
Q
Which of the following best describes the mechanism of nucleophilic
addition?
A
A nucleophile attacks a carbonyl carbon, forming a tetrahedral
intermediate before adding to the molecule
6
Q
In the reaction of an aldehyde with a Grignard reagent (RMgX), the Grignard reagent acts as
the
A
Nucleophile
7
Q
In the titration of a weak acid with a strong base, what causes the pH to rise significantly after the equivalence point?
A
The excess OH- from the strong base increases
the pH
8
Q
The excess OH- from the strong base increases the pH
A
The weak acid does not dissociate completely, so fewer H+ ions are available
9
Q
What is the primary purpose of the cold lime process in water treatment?
A
To soften hard water by removing calcium and magnesium ions
10
Q
Which of the following is a key chemical used in the cold lime process for softening water?
A
Calcium hydroxide
11
Q
What is the primary purpose of an equalization pond in wastewater treatment?
A
To store and stabilize fluctuating flows of wastewater before treatment
12
Q
Which of the following is NOT a primary function of an equalization pond in wastewater treatment?
A
To provide long-term storage for treated wastewater
13
Q
The Clausius-Clapeyron equation describes the relationship between the vapor pressure of a substance and its temperature.
What does the slope of the vapor pressure curve represent?
A
The enthalpy of vaporization
14
Q
Which of the following factors does NOT directly affect the slope of the vapor pressure curve according to the Clausius-Clapeyron equation?
A
Molecular weight of a substance
15
Q
The resistivity of a material typically increases with an increase in temperature. This behavior is
most commonly observed in
A
Conductors
16
Q
In semiconductors, as temperature increases, the resistivity
A
Decreases
17
Q
Oxidizers are substances that
A
Can provide oxygen to support combustion
18
Q
The oxidizer symbol used in the Globally Harmonized System (GHS) of Classification and Labeling of Chemicals (CLP) is represented as:
A
A flame over a circle
19
Q
In a cyclic process, the work done by the system is equal to
A
The heat absorbed by the system
20
Q
In a cyclic process, the total change in the internal energy of the system is
A
Zero
21
Q
Why is sulfuric acid often used as a catalyst in esterification?
A
It accelerates the reaction by acting as a dehydration agent
22
Q
In Fischer esterification, which of the following is typically used as a catalyst?
A
Sulfuric acid
23
Q
The oxidizer symbol used in the Globally Harmonized System (GHS) of Classification and Labeling of Chemicals (CLP) is represented as:
A
A flame over a circle
24
Q
Which of the following methods is considered the most economical for producing aluminum matrix composites (AMCs)?
A
Stir casting
25
Which of the following factors has the most significant impact on the production cost of aluminum matrix composites?
Type of reinforcement material
26
What is the primary purpose of adding carbon to iron in the production of steel?
To increase the tensile strength and hardness of the material
27
How does carbon affect the microstructure of steel?
It leads to the formation of cementite and pearlite
28
A levorotatory compound
Rotates plane-polarized light to the left
(counterclockwise)
29
A dextrorotary compound
Rotates plane-polarized light to the right (clockwise)
30
Does not affect plane-polarized light
achiral
31
A compound that has a mirror-image structure
enantiomer
32
Which of the following is true for a dextrorotatory compound?
It is denoted as D
33
What is the ratio of **stress to strain** in the elastic region of a material called?
Young's modulus (resistance to change in length under tension)
34
Contraction strain/ longitudinal strain
Possion's ratio
35
Pressure increase/volume decrease
Bulk modulus (resistance to compression)
36
Shear stress/shear strain
Shear modulus (resistance to deformation)
37
What are the units of Young’s Modulus?
N/m^2
38
What is the main role of volatile organic compounds (VOCs) in air pollution?
They contribute to the formation of ground-level ozone and smog
39
Which of the following is a major source of volatile organic compounds (VOCs) in urban areas?
Motor vehicle exhaust
40
Which of the following best describes Scope 1 emissions in the context of the Greenhouse Gas (GHG) Protocol?
Direct emissions from owned or controlled sources
41
Which of the following is an example of Scope 1 GHG emissions?
Emissions from a company’s own fleet of delivery trucks
42
What does the term cis refer to in the context of geometrical isomerism?
two substituents are on the same side of a double bond or ring
43
Which of the following compounds exhibits cis-trans isomerism?
1,2-dichloroethene
44
In a body-centered cubic unit cell, where is the atom located in the unit cell?
The atom is located at both the center and the corners
45
In a body-centered cubic (BCC) structure, how much of an atom located at the corner of the unit cell contributes to the overall structure?
1/8 atom
46
Which of the following is a colligative property that decreases the temperature at which a solution freezes compared to the pure solvent?
Freezing point depression
47
What is the role of the Van’t Hoff factor (i) in the freezing point depression formula?
It accounts for the number of solute particles in solution due to **dissociation**
48
What is hybridization in chemistry?
The mixing of atomic orbitals to form new, identical hybrid orbitals
49
What is the molecular geometry around the oxygen atom in **dimethyl ether**?
bent
50
What is the standard enthalpy of formation of an element in its most **stable form**?
zero
51
The standard enthalpy change of a reaction can be calculated using
Hess' law
52
If the standard enthalpy of formation of a compound is negative, what does this indicate?
The reaction is exothermic
53
Which of the following is the major consideration that influences the rate of **electron oxidation** in a chemical reaction?
The concentration of the oxidizing agent
54
What is a mutagen?
An agent that causes changes in DNA
55
In which type of crystal lattice structure do ions arrange themselves in a repeating pattern that minimizes repulsion and maximizes attraction?
Close-packed lattice
56
Why does the pH of a weak acid increase when its concentration is decreased?
The concentration of hydrogen ions decreases
57
Which of the following is the major consideration that influences the rate of **electron oxidation** in a chemical reaction?
The concentration of the oxidizing agent
58
Which of the following crystal lattice structures is considered the most stable for ionic compounds?
Face-centered cubic
59
What is the result of a silent mutation in DNA?
The mutation does not change the amino acid sequence of the protein
59
What role does temperature play in the rate of **electron oxidation reactions?**
Higher temperature generally increases the rate of oxidation
60
What is the relationship between the acid dissociation constant (KA) and the pH rise in a
weak acid solution?
Lower KA values lead to a larger pH rise
61
What is DNA synthesis?
The process of copying DNA to produce identical strands
62
What is the function of DNA helicase during DNA replication?
It unwinds the double-stranded DNA
63
Which enzyme is responsible for sealing nicks (gaps) in the sugar-phosphate backbone of DNA
during replication and repair?
DNA ligase
64
Which molecule brings amino acids to the ribosome during translation of mRNA?
tRNA
65
The equivalence point in a titration is defined as
The point at which the number of moles of acid equals the number of moles of base
66
At the equivalence point in an acid-base titration
The point at which the number of moles of acid equals the number of moles of base
67
At the equivalence point in an acid-base titration
The reactants are present in stoichiometric amounts
68
Which of the following formulas is used to calculate chlorine demand in water treatment?
Chlorine demand = total chlorine – free chlorine
68
What is chlorine demand in water treatment?
The amount of chlorine that reacts with impurities and is not available as residual
69
What is the first step in properly managing hazardous chemical waste?
Identifying and labeling the waste correctly
70
What is the most appropriate method for disposing of hazardous chemical waste in a laboratory?
Storing it in sealed containers for authorized disposal
71
On a stress-strain curve, the yield strength is defined as
The point where permanent deformation begins
72
Where on the stress-strain curve is the yield strength point typically located?
Just before the curve flattens or shows a noticeable change in slope
73
On a stress-strain curve, the area under the curve
Modulus of toughness = energy absorbed per unit volume
74
On a stress-strain curve, the point where the materials break
Fracture or breaking point
75
What are stereoisomers?
Isomers with the same molecular formula and atom connectivity but different spatial arrangements
76
A compound has 3 chiral centers. Under what condition might it have fewer than 8 stereoisomers?
If the molecule has internal symmetry (meso compounds)
77
What does the coordination number in an ionic crystal refer to?
The number of oppositely charged ions
surrounding a given ion
78
How does a higher coordination number affect the stability of an ionic structure?
It increases the stability due to stronger electrostatic attraction
79
Where are filamentous bacteria like
Actinobacteria most commonly found?
Soil environment
80
Which of the following is a well-known genus of
filamentous bacteria involved in antibiotic
production?
Streptomyces
81
Example of rod-shaped bacteria
Escherichia
Clostridium
82
Where are filamentous bacteria like
Actinobacteria most commonly found?
Soil environment
83
Example of spherical bacteria
Streptococcus
84
What is the gravimetric factor used for in gravimetric analysis?
To convert the mass of a weighed compound to the mass of the analyte
85
What is the precipitate formed when equal amounts of BaCl2 and Na2SO4 are mixed in aqueous solution?
BaSO4
86
Which pair of ions will form a precipitate when mixed?
Ag+ and Cl-
87
In forensic science, DNA fingerprinting is mainly used to
Identify suspects or victims
88
What is the primary purpose of restriction enzymes in DNA fingerprinting?
To cut the DNA into specific fragments
89
Why is PM 2.5 more hazardous to human health than PM 10?
PM 2.5 can penetrate deeper into the lungs and bloodstream
90
Which of the following health conditions is PM 2.5 more likely to cause compared to PM 10?
Chronic respiratory diseases like asthma and bronchitis
91
According to Beer-Lambert Law, what happens to the absorbance of a solution if the concentration of the
absorbing species is doubled?
The absorbance doubles
92
Why does the absorbance increase linearly with concentration, assuming Beer-Lambert Law holds?
Because more solute particles absorb more light proportionally
93
What is transmittance in the context of
**spectrophotometry**?
The ratio of transmitted light to incident light
94
Which has the highest heat of hydrogenation?
ethene
95
In what year was the first Bose-Einstein
Condensate (BEC) successfully created in a laboratory, and which element was used?
1995 – Rubidium (Rb)
96
What type of bonding is present in the diamond structure?
covalent
97
How many atoms are there in a unit cell of the diamond structure?
4
98
Why is hydrocarbon density important in the petroleum industry?
It helps classify crude oil and fuels
99
Where does the Krebs cycle occur in eukaryotic cells?
Mitochondrial matrix
100
The NADH and FADH2 produced in the Krebs cycle are primarily used for
ATP production in the electron transport chain
101
What type of chemical reaction is esterification?
Condensation
102
The reaction between ethanol and acetic acid produces
Ethyl acetate
103
Where is the genetic material located in a prokaryotic cell?
Nucleoid region
104
In which organelle besides the nucleus can genetic material be found in a eukaryotic cell?
Mitochondria
105
If the chemical potential of component A in a mixture increases, what is the likely result?
Component A leaves the mixture
106
Why is chirality important in drug manufacturing?
Enantiomers of a drug can have different biological effects
107
Which of the following best describes enantiomers in drug chemistry?
Molecules that are mirror images but not superimposable
108
Which advanced method is effective for removing low concentrations of phosphorus from treated water?
Reverse osmosis
109
Which of the following is NOT an effective method for phosphorus removal from water?
Sand filtration alone
110
What does Scope 2 GHG emissions refer to?
Indirect emissions from the generation of purchased electricity, steam, heating, and cooling
111
What occurs at the anode in an electrochemical cell?
oxidation
112
In an electrolytic cell, which electrode is the anode?
The one connected to the positive terminal of the power source
113
What is a Bose-Einstein Condensate (BEC)?
A state of matter formed near absolute zero where particles occupy the same quantum state
114
Which two scientists predicted the existence of Bose-Einstein Condensate in the 1920s?
Satyendra Nath Bose and Albert Einstein
115
Which of the following greenhouse gases has the highest Global Warming Potential (GWP) over a 100 yr time horizon?
Sulfur hexafluoride (24,300)
116
What is the main purpose of IUPAC naming?
To create standardized names for chemical compounds so they can be universally recognized
117
What is the IUPAC name of C6H5CH2CH3?
Ethylbenzene
118
Which compound would release the most heat upon regeneration?
1,3-cyclohexadiene
119
Which of the following will have the lowest heat of hydrogenation?
Benzene
120
Which indicator is most appropriate for titrating 0.1 M HCl with 0.1 M NaOH?
Bromothymol blue (pH range 6 – 7.6)
121
Which of the following statements is true regarding diastereomers?
Diastereomers differ at some but not all chiral centers
122
Which of the following pairs of compounds are diastereomers but not enantiomers?
(R,R)-2,3-dibromobutane and (R,S)-2,3-dibromobutane
123
Which of the following best describes the compressibility factor (Z)?
It is the ratio of PV of a real gas to nRT
124
It is the ratio of real gas pressure to ideal gas pressure
fugacity
125
At very high pressures, most real gases exhibit a compressibility factor greater than 1. Why?
Intermolecular repulsion increases gas volume
126
Which parameter is most critical for assessing the ability of wastewater to support aerobic biological treatment processes?
Dissolved oxygen
127
Which of the following gases is most likely to have Z significantly less than 1 at room temperature and moderate pressure?
ammonia
127
Which of the following factors decrease the dissolved oxygen level in wastewater?
High organic matter content
128
How does chlorine from chlorofluorocarbons (CFCs)
affect the ozone layer?
It breaks down ozone molecules in the
stratosphere
129
One chlorine atom from a CFC can destroy approximately how many ozone molecules before being deactivated?
100, 000 (1 CFC = 100,000 ozone)
130
What is the SI unit of energy?
joule
131
Which of the following is an example of potential energy?
A compressed spring
132
Which type of isomerism is shown by butane and methylpropane?
Chain isomerism
133
Which of the following is an example of structural isomerism?
Glucose and fructose
134
CRISPR was originally discovered as part of the immune system in
Bacteria and archaea
135
What is the role of the Cas9 protein in the CRISPR-Cas9 technique?
It cuts the DNA at a specific location
136
Which of the following is the primary driving force that causes water to pass through the membrane in a reverse osmosis process?
Hydraulic pressure
137
The mechanical pressure applied in reverse osmosis must be
Higher than the osmotic pressure to force water through the membrane
138
Which of the following best describes digestion in gravimetric analysis?
It involves gently heating the precipitate to allow it to grow larger and purer
139
What is the primary purpose of digestion in gravimetric analysis?
To ensure complete precipitation of the analyte
140
The carbonyl group is present in all of the following except
alcohol
141
What is the primary purpose of digestion in gravimetric analysis?
To ensure complete precipitation of the analyte
142
Which of the following compounds contain a triple bond between carbon atoms?
Ethyne
143
Which of the following is a characteristic feature of hydrocarbons with triple bonds?
They are unsaturated and highly reactive
143
Which of the following is a key advantage of thermoplastics over
thermosets?
Thermoplastics can be remelted and reshaped multiple times without degrading
144
Which application would most benefit from using thermoplastics instead of thermosets?
Reusable packaging containers
145
What is E/Z isomerism?
A type of stereoisomerism due to restricted rotation around a double bond
146
Which rule is used to assign priority to groups attached to a double bond in E/Z isomerism?
Cahn-Ingold-Prelog priority rules
147
How many standard sections are there in a Safety Data Sheet (SDS) according to the Globally Harmonized System (GHS) of Classification and Labeling of Chemicals?
16
148
Which SDS section provides information about the chemical’s recommended uses and restrictions?
Section 1
149
Which compound contains a carbon atom double bonded to oxygen and also single bonded to another oxygen atom that is bonded to a carbon chain?
Ester
150
In the context of EPR (Extended Producer Responsibility) Laws, what does “take-back” refer to?
Producers are responsible for collecting and managing waste from their products after consumer use
151
What is the main goal of Extended Producer Responsibility (EPR)?
To shift the environmental responsibility of waste from consumers to producers
152
What does the Gibbs free energy represent in a thermodynamic system at constant pressure and temperature?
Maximum usable energy available to do work
153
What are elastomers?
Polymers that can return to their original shape after stretching
154
What is the main long-term energy storage molecule in animals?
fat
155
What happens to excess glucose in animal cells?
It is stored as glycogen or converted to fat
156
Why is cast iron preferred over steel in some chemical reactor vessels?
Cast iron is more corrosion-resistant than steel
157
What is a key mechanical advantage of cast iron over steel in the context of chemical reactors?
Cast iron has better wear resistance and can withstand higher temperatures
158
Which of the following indicators is commonly used in EDTA titrations to detect the endpoint?
Eriochrome Black T
159
Which of the following is a common example of redox titration?
Titration of iodine with sodium thiosulfate
