Physical Chemistry

Question 1

An ideal gas will only be considered in the following operating parameters

a. High T, High P
b. High T, Low P
c. Low T, High P
d. Low T, Low P

Answer 1

b.

Question 2

Which of the following is false regardung absolute zero

a. Absolute zero can be achieved
b. All molecules will stop moving
c. Temperature is 0Kelvin
d. Temperature is 0Rankine

Answer 2

a.

Absolute zero is a THEORETICAL state and cannot be achieved

Question 3

For a real gas what causes deviation from the ideal pressure at the molecular level

a. Energy is lost for each collision against the sides of the container
b. Energy is lost due to the collision of molecules with one another.
c. Intermolecular forces of attraction of the molecules with one another.
d. Molecules randomly hit the sides of the wall with less force than usual.

Answer 3

c

Question 4

when gas molecules collide, they experience ________ collision

a. Perfectly elastic
b. Imperfect elastic
c. Perfectly inelastic
d. Imperfect inelastic

Answer 4

a
Perfectly elastic - bounces off
Inelastic - deforms
Perfectly Inelastic -sticks together
Explosion - reverse of Perfectly inelastic

Question 5

Which of the following is false with KMT

a. gas molecules move in random motion.
b. The temperature of the whole system does not change with time
c. Due to collision of gas molecules with each other, some kinetic energy is lost
d. The size of the molecules are negligible

Answer 5

c because it is perfectly elastic, meaning KE is preserved

Question 6

This is the pressure exerted by the gas molecules that are in equilibrium with a liquid

Partial Pressure
Atmospheric Pressure
Total Pressure
Vapor Pressure

Answer 6

Vapor Pressure

Question 7

The internal energy of an ideal gas depends on

Volume
Absolute Temperature
Pressure
Number of moles

Answer 7

Absolute Temperature

Question 8

Which of the following is a characteristic of an adiabatic process

a. delta U=0
b. W=0
c. Q=0
d. delta V=0

Answer 8

c

Question 9

which of the following is not conserved in any process?

Mass
Energy
Momentum
Entropy

Answer 9

Entropy

Question 10

Increasing the temperature of the cold reservoir ______ the Carnot Efficiency

Inc
Dec
Does not change

Answer 10

Decreases

Question 11

If the entropy of a system decreases, the entropy of its surroundings

a. Must always increase
b. Must always decrease
c. May increase or decrease
d. Not enough information to answer the question

Answer 11

a
- because Delta S univ > 0 meaning if S system decreases, S surroundings will always increase to counteract it

Question 12

The amount of heat absorbed when CO, gas reacts with a solid CaO to form solid CaCO, is measured in a bomb calorimeter. The data obtained give a direct measure of:

a. Delta U
b. V delta P
c. delta H
d. Cp

Answer 12

a
- because Bomb Calorimeter is V=k

Question 13

Heat required to raise the temperature of 1lb of water by 1F

Answer 13

BTU

Question 14

Heat required to raise the temperature of 1g of water by 1C

Answer 14

Calorie

Question 15

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.

a. 1 only
b. Both 1 and 2
c. 2 only
d. None of the above

Answer 15

b

Question 16

The general statement of the Third Law of Thermodynamics is attributed to:

a. Nikolaus Otto
b. Jacobus Clapeyron
c. William Clausius
d. Walther Nernst

Answer 16

d

• In 1912 Walther Nernst was able to formulate the third law of thermodynamics, which made it possible to calculate chemical equilibriums on the basis of the heat exchange.

Question 17

The equilibrium intensive state of a system is described by specifying the temperature, pressure, and:

a. Mole fractions
b. Number of moles
c. Volume
d. Chemical potential

Answer 17

a.

Question 18

The fugacity of a real gas is equal to:

a. The pressure of an ideal gas which has the same chemical potential as the real gas
b. The pressure of a real gas which has the same chemical potential as the ideal gas
C. The chemical potential of an ideal gas which has the same pressure as the real gas
d. The chemical potential of a real gas which has the same pressure as the ideal gas

Answer 18

a

Question 19

(Oct. 2021 PBE)

An adiabatic process is one in which the system under investigation is thermally isolated so that there is no exchange of heat with the surroundings. Thus, the work done on a closed system in an adiabatic process is

a. Equal to zero
b. Not equal to the exchange of heat with surroundings
c. Equal to the increase in internal energy of the system
d. Not equal to the increase in internal
energy of the system

Answer 19

c

Question 20

(Nov. 2019 PBE)

State Le Chatelier’s Principle.

a. 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.
b. All of these
c. 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.
d. 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

Answer 20

a

Question 21

(Nov. 2019 PBE)

Define entropy,

a. Entropy is a function of the state of the system and determines whether a physical change or chemical reaction can occur simultaneously in a closed system
b. Entropy is the opposite of enthalpy
c. Entropy determines the time required for a reaction to proceed and complete
d. All of these

Answer 21

d

Question 22

A method for determining the mol weight of gas that is gaseous at room temperature

Answer 22

Regnault’s Method

Question 23

A method for determining mol weight of gas in vapor phase of readily volatile liquids

Answer 23

Dumas Method

Question 24

It is the adhesion of atoms, ions, or molecules from a gas, liquid or dissolved solid to a surface.

Answer 24

Adsorption

Question 25

At absolute zero, all substances would be in the _________ phase, and all particles would have __________kinetic energy.

Answer 25

solid, zero

Question 26

Asolute zero is equal to zero in the ___________ temperature scale

Answer 26

Kelvin

Question 27

Considered the fourth state of matter

Answer 27

Plasma

Question 28

It is a mixture of neutral atoms, charged ions, and free electrons

Answer 28

Plasma

Question 29

special state of matter in which atoms in a confined gas act together like a single giant particle after being cooled cryogenically to a temperature near absolute zero

Answer 29

Bose-Einstein Condensate

Question 30

Molecular weight determination Having various pressures and constant temperature. Use: a. Method of Limiting Density b. Vapor density Method c. Regnault Method

Answer 30

a

Question 31

Molecular weight determination Determining molecular weight in vapor phase of volatile liquid. Use: a. Method of Limiting Density b. Vapor density Method c. Regnault Method

Answer 31

b

Question 32

He developed Vapor Density Method

Answer 32

Jean Baptiste Andre Dumas

Question 33

Molecular weight determination Determining molecular weight of a gas at room temp. Use: a. Method of Limiting Density b. Vapor density Method c. Regnault Method

Answer 33

c

Question 34

Compression factor Z for ideal gas

Answer 34

1

Question 35

The temperature at which the property of a real gas coincides with that of an ideal gas Absolute temp Ideal Temp Boyle Temp Transitioning temp

Answer 35

Boyle Temperature

Question 36

It means that the vapor pressure of the system is in equilibrium with its liquid state

Answer 36

Saturated vapor pressure

Question 37

At critical point, physical properties of liquid and vapor are ______

Answer 37

equal

Question 38

Amount of work required to increase the surface area of a liquid by one unit of area

Answer 38

Surface Tension -property of a liquid that allows it to resist an external force

Question 39

It is the existence of substances in more than one modification

Answer 39

Polymorphism

Question 40

In electrolytic cells, the anode is _______ and the cathode is ________ positive negative

Answer 40

positive, negative

Question 41

In galvanic cells, the anode is _______ and the cathode is ________ positive negative

Answer 41

negative, positive

Question 42

"The mass of a substance involved in the reaction at the electrode is proportional to the quality of electricity passes through the solution"

Answer 42

Faraday's Law

Question 43

According to this law, at constant pressure and temperature, molecules or atoms with lower molecular mass real a few faster than the higher molecular mass molecules or atoms.

Answer 43

Graham's Law - lighter gas will travel faster than heavier gas

Question 44

The fastest gas

Answer 44

Helium

Question 45

according to Graham, slow rate of effusion of gas is inversely proportional to the square root of its atomic mass molecular mass molar mass isotopic mass

Answer 45

molecular mass

Question 46

Which of the following statement is CORRECT about ideal gas? a. The pressure of the gas is equal to the total kinetic energy of the molecules in a unit volume of the gas b. The product of pressure and volume of the gas is always constant c. The average kinetic energy of molecule of the gas is proportional to its absolute temperature d. The average kinetic energy of molecule of the gas is proportional to the square root of its absolute temperature

Answer 46

c

Question 47

absolute zero maybe regarded as that temperature at which a. all gases becomes liquid b. molecular motion ceases c. all substances are solids d. water freezes

Answer 47

b

Question 48

if a given gas has a compressibility factor, Z>1, this means that ___________ between the molecules of gases a. attractive forces b. repulsive forces c. negligible forces of attraction d. negligible replusive forces

Answer 48

b. Z>1 rep forces ate dominant Z<1 att forces are dominant Z inc with P

Question 49

Generally, viscosity of gases _______ as temperature increases a. remains constant b. increases c. approaches unity d. decreases

Answer 49

b

Question 50

Fluids whose viscosity increases as shear rate increases. a. Dilatant c. Newtonian b. Pseudoplastic d. Bingham plastic

Answer 50

Dilatant -shear thickening = increasing viscosity as more force is applied ex: oobleck • Newtonian - constant viscosity, with zero shear rate at zero shear stress, that is, the shear rate is directly proportional to the shear stress. ex : water • Pseudoplastic - shear thinning; decrease in viscosity when more force is applied • Bingham - behaves as a rigid body at low stresses but flows as a viscous fluid at high stress.

Question 51

Fluids whose viscosity increases with time at constant shear rate. a. Inviscid b. Rheopectic c. Thixotropic d. Pascalian

Answer 51

b • Inviscid - negligible viscosity and shear rate. no viscosity. • Thixotropic - viscosity decreases with time at constant shear rate. • Pascalian - pressure at any point in the fluid is equal in all direction

Question 52

What happens to the molecules in a liquid when the liquid is heated and vapor starts to form? a. the intramolecular forces between liquid molecules are disrupted b. the intermolecular forces between liquid molecules are disrupted c. kinetic energy is removed from the system d. London forces become stronger

Answer 52

b • Intramolecular forces are the forces that hold atoms together within a molecule. • Intermolecular forces are forces that exist between molecules

Question 53

One colligative property of solutions is its freezing point depression. Which observation will show that the solute is an electrolyte (Delta Tf/m)? a. is not a constant c. is less than Kf b. is not Kf d. is greater than Kf

Answer 53

d

Question 54

Which of these 0.1 m solutions will give the highest boiling point at 1 atm? a. table salt solution c. barium chloride b. sugar solution d. potassium chloride

Answer 54

b. higher MW, higher conc = higher BP

Question 55

All the half cell potential e°, use the ______ as the reference Hydrogen electrode oxygen half cell carbon half cell arbitrary net zero point

Answer 55

a

Question 56

An electrochemical cell in which chemical reaction is forced to occur by the application of an outside source of energy is a. galvanic b. electrolytic c. electrical d. chemical

Answer 56

b

Question 57

The more negative the value of e°, the more likely the reaction is to proceed from a. left to right b. right to left c. either way d. can't be determined

Answer 57

b

Question 58

Which of the following statements about colligative properties is TRUE? a. Both vapor pressure and freezing point INCREASE when a non- volatile solute is added to a solvent. b. Both freezing point and boiling point INCREASE when a non- volatile solute is added to a solvent. c. Both vapor pressure and boiling point DECREASE when a non- volatile solute is added to a solvent. d. Colligative properties depend only upon the NUMBER of solute particles in a solution and not upon their identity.

Answer 58

d

Question 59

The vapor pressure of a liquid a. always increases with temperature b. always decreases with temperature c. is independent of temperature d. none of these

Answer 59

a

Question 60

The law relating the solubility of the gas to its pressure is called a. Raoult's Law b. Distribution Law c. Henry's Law d. Arrhenius' Law

Answer 60

b

Question 61

When gaseous ammonia is dissolved in water, the resulting solution does not obey Henry's Law. Which of the following best explains why this solution does not obey Henry's Law? a. All of the NH, that initially dissolves in the water rapidly escapes from the solution because NH, is a gas at room temperature b. NH, reacts with the solvent to produce ammonium and hydroxide ions c. NH, is not soluble in water because it is a non-polar molecule. d. The hydrogen bonding between ammonia molecules is so strong that NH, cannot be dissolved in water.

Answer 61

b Henry's Law C=k*P k- Henrys constant P- Partial pressurr

Question 62

For a chemical reaction in a state of equilibrium, a decrease in temperature will a. favor the reaction that is exothermic b. favor the reaction that is endothermic c. have no effect on the system d. increase the equilibrium constant of the system

Answer 62

a The system counteracts the change by producing more heat.

Question 63

In a chemical reaction, equilibrium has been established when the a. opposing reaction ceases c. reaction ceases to generate heat b. concentrations are equal d. net velocities of reactions is zero

Answer 63

d • In a reversible chemical reaction, equilibrium is said to have been established when the speeds of opposing reactions become equal. Neither the forward reaction nor the backward reaction has ceased. • Hence, the state of equilibrium refers to the dynamic state

Question 64

For a chemical reaction in a state of equilibrium, an increase in temperature will a. favor the reaction that is exothermic b. favor the reaction that is endothermic c. have no effect on the system d. increase the equilibrium constant of the system

Answer 64

b The system counteracts the change by absorbing the extra heat.