Concept Phy Chem

Question 1

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

Answer 1

High temperature, Low Pressure

Question 2

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

Answer 2

Absolute zero can be achieved

Question 3

For a real gas, what causes the deviation from
the ideal pressure at a 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. Intermolecularforces of attraction of the
molecules with one another
d. Molecules randomly hit the sides of the
wall with less force than usual

Answer 3

Intermolecular forces of attraction of the
molecules with one another

Question 4

When gas molecules collide, they experience
_collision.

Answer 4

Perfectly elastic

Question 5

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

Answer 5

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

Question 6

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

Answer 6

Vapor pressure

Question 7

The internal energy of an ideal gas depends on:

Answer 7

Absolute temperature

Question 8

The state of an ideal gas is changed in a closed
path 1→2→3→4→1. Which of the following is
true about the work done on the gas?

a. W12>0, W23=0, W34<0, W41=0
b. W12<0, W23=0, W34=0, W41>0
c. W12=0, W23>0, W34=0, W41<0
d. W12=0, W23<0, W34=0, W41>0

Answer 8

W12=0, W23<0, W34=0, W41>0

Question 9

Which of the following is a characteristic of an
adiabatic process?

Answer 9

Q=0

Question 9

A sample of an ideal gas has an internal energy
of U and is then compressed to 1⁄2 of its original
volume while the temperature stays the same.
What is the new internal energy of the ideal gas
in terms of U?

Answer 9

U

Question 10

Which of the following is not conserved in any
process?

Answer 10

Entropy

Question 11

An isentropic process is:

Answer 11

Reversible and adiabatic

Question 12

Increasing the temperature of the cold reservoir__
the Carnot efficiency.

Answer 12

Decreases

Question 13

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

Answer 13

Must always increase

Question 14

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:

Answer 14

ΔU

Question 14

Heat required to raise the temperature of 1lbm
of water by 1 ̊F.

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.

Answer 15

both

Question 16

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

Answer 16

Walther Nernst

Question 17

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

Answer 17

Mole fractions

Question 18

The fugacity of a real gas is equal to:

Answer 18

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

Question 19

Conceptual Question (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

Answer 19

Equal to the increase in internal energy
of the system

Question 20

Conceptual Question (Oct. 2021 PBE)
If enthalpy is defined as present in a constant
pressure process change of state, using the
relationship of ΔH=ΔU+ΔPV, where H is enthalpy,
U is the energy change in the system and PV
represents pressure and volume states,
determine the ΔU and ΔH of 1kg of water when
vaporized at constant temperature of 100 ̊C and
constant pressure of 101.35kPa. The specific
volumes of liquid and vapor water are 0.001041
and 1.67m3/kg. An amount of 2257kJ of heat is

added to the water.

Answer 20

ΔU=2087kJ; ΔH=2257kJ

Question 21

Conceptual Question (Oct. 2021 PBE)
A certain gas confined in a cylinder by a piston,
where the initial pressure in the system is 7 bar
and the volume is 0.11 cubic meter. The piston is
held in place by latches and the apparatus is in
vacuum. Determine the change in energy when
the latches are removed suddenly and the gas
expands to double its initial volume and the
piston strikes the latches at the end of the
process.

Answer 21

No change

Question 22

Conceptual Question (Nov. 2019 PBE)
State Le Chatelier’s Principle.

Answer 22

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.

Question 23

Determine which of the following occurrences tells us what happens when Le Chatelier’s principle is applied whether these are true or false. 1. The addition of a component causes the equilibrium to shift to the opposite side 2. The removal of a component causes the equilibrium to the side from which the component is removed 3. Increasing the temperature drives an exothermic reaction to the side of the reactants, an endothermic equilibrium to the side of the products 4. The addition of a catalyst has NO effect on the position of the equilibrium

Answer 23

T, T, T, T

Question 24

Determine whether the changes in entropy (ΔS) and enthalpy (ΔH) are positive, negative, or near zero. 1. Ethyl alcohol evaporating from glass container 2. A diatomic molecule dissociates into atoms 3. Charcoal is burned to form CO2 and water

Answer 24

ΔH>0, ΔS>0; 2. ΔH>0, ΔS>0; 3. ΔH>0, ΔS>0

Question 25

Conceptual Question (Nov. 2019 PBE) Choose the process that occurs with a decrease in entropy.

Answer 25

Freezing of water

Question 26

Conceptual Question (Nov. 2019 PBE) Which of the following does not have a zero enthalpy of formation at 298.15K?

Answer 26

a.Li(g)

Question 27

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

Answer 27

Viscosity

Question 28

The Clapeyron Equation gives the slope:

Answer 28

dP/dT

Question 29

The Clausius-Clapeyron Equation does NOT apply to: a. S-V equilibrium c. S-L equilibrium b. L-V equilibrium

Answer 29

S-L equilibrium

Question 30

Conceptual Question (Nov. 2019 PBE) What is the Clapeyron Equation? a. Any of these b. 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. c. 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. d. It postulates that if the temperature and pressure are both change in such a way asto keep the chemical potentials of two phases equal to each other, the rates of change are given by the equation.

Answer 30

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

Question 31

Conceptual Question (Oct. 2021 PBE) 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?

Answer 31

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

Question 32

For miscible systems, the boiling point of the solution is:

Answer 32

Between the boiling points of the two liquids

Question 33

All colligative properties stem from the _ of the chemical potential of the liquid solvent as a result of the presence of the solute.

Answer 33

Reduction

Question 34

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.

Answer 34

Equal to

Question 35

When a solute is introduced to a liquid system, the entropy of the said system:

Answer 35

Increases

Question 36

Among the following, which compound will produce the least lowering of the vapor pressure of a solution?

Answer 36

sucrose, C12H22O11

Question 37

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

Answer 37

Trouton’s rule fails for highly polar liquids

Question 38

Conceptual Question (Nov. 2019 PBE) Are galvanic cells and electrolytic cells the same? Why?

Answer 38

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

Question 39

Significance of colligative property in physical chemistry

Answer 39

it refers to the freezing point depression, boiling point elevation, osmotic pressure and lowering of the vapor pressure by a non volatile solute.