1

Quiz

Which quantities are state functions? In Joule's free expansion experiment,

(A) W (A) q=0
(B) q (B) W=0
(C) U (C) ΔU=0
(D) H (D) P=0
(E) T=0
For the cycle A->B->C->A as shown in
Figure 1, ΔU is For an ideal gas performing expansion from
(A) Positive P1 to P2, the work done by the gas in
(B) Zero reversible isothermal process is Wi and the
(C) Negative work done by the gas in reversible adiabatic
process is Wa.
For the cycle A->B->C->A as shown in (A) Wi>Wa
Figure 1, the work (W) done by the gas is (B) Wi=Wa
(A) positive (C) Wi<Wa
(B) zero
(C) Negative In adiabatic expansion of gases, the
temperature of the gas
Consider the two paths from A->B shown in (A) increases
Figure 2, which path has performed larger (B) stays the same
W, (C) decreases
(A) Path 1
(B) Path 2

The heat required to heat up a certain

amount of gas by ΔT at constant pressure is
Qp. The heat required to heat up the same
amount of gas by the same ΔT at constant
volume is Qv.
(A) Qp>Qv
(B) Qp=Qv
(C) Qp<Qv

In reversible adiabatic process,

(A) PV=constant
(B) PV^γ=constant
(C) P/V^γ=constant
(D) P/V=constant

The equation of a straight line in P-V

diagram is
(A)P=aV^2+b
(B)P=aV+b
(C)P=a/V+b
(D)P=a/V^2+b
2
Quiz
Certain amount of a monatomic ideal gas One mole of an ideal gas A at temperature 100K
contained adiabatically is suddenly released to a is mixed with one mole of ideal gas A at
lower pressure. As a result of the irreversible temperature 300K. If the mixing is done in an
expansion, certain amount of work, Wirr, is adiabatic enclosure, what is the final temperature
performed. The final temperature is found to be after mixing?
Tirr. It is known that the final temperature and (A) >200K
work performed would have been Trev and (B) 200K
Wrev if the expansion were done reversibly. (C) <200K
Indicate Tirr is
(A) larger One mole of an ideal gas A at temperature 100K
(B) equal to is mixed with one mole of ideal gas A at
(C) smaller than Trev temperature 300K. If the mixing is done
reversibly, what is the final temperature after
In the same conditions as above: mixing?
Wirr is (A) >200K
(A) larger (B) 200K
(B) equal to (C) <200K
(C) smaller than Wrev
For an ideal gas undergoing irreversible
A small object at 600K is thrown into a big tank adiabatic expansion,
at 300K. The tank is so big that the temperature (A) q=0, ΔS=0
stays the same with the addition of the small (B) q=0, ΔS≠0
object. The total entropy change is ΔS1-step. (C) q≠0, ΔS=0
Consider that the same small object at 600K is
thrown into an intermediate big tank at 400K
For free expansion of ideal gas,
first, and then transferred to the big tank at
300K. The total entropy change is ΔS2-step.
(A) W=0
ΔS1-step is (B) q=0
(A) larger (C) ΔU=0
(B) equal to (D) ΔH=0
(C) smaller than ΔS2-step (E) ΔS=0

Consider that the same small object at 600K is An ideal gas has its pressure reduced from P1 to
thrown into an intermediate big tank at 400K P2. When the reduction is done in a reversible
first, and then transferred to the big tank at isothermal path, the entropy change of the gas is
300K. If the entropy change of the object is ΔS1. When the reduction is done in a reversible
ΔSobject. For the two different processes, we adiabatic path, the entropy change is ΔSa. ΔSi is
will have ΔSobject,1-step and ΔSobject,2-step. (A) larger
Note that ΔSobject,2-step is the sum of the (B) equal to
entropy change of the two steps. ΔSobject,1-step (C) smaller than ΔSa
is
(A) larger When the reduction is done in a constant-
(B) equal to volume process, the entropy change of the gas is
(C) smaller than ΔSobject,2-step ΔSv. ΔSv is
(A) larger
(B) equal to
(C) smaller than ΔSa
3
Quiz
A rigid container is divided into 2 For regular solutions, the activity coefficient
compartments of equal volume by a γ increases with increasing temperature.
partition. One compartment contains 1 mole True or False?
ideal gas A at 1 atm, and the other contains
1 mole of ideal gas B at 1 atm. What is the A steam engine operating between high
entropy change ΔS when the partition temperature T2 and low temperature T1 has
between the two compartments is removed? a maximum efficiency of
(A) ΔS>0 (A) 1-T1/T2
(B) ΔS=0 (B) 1-(T1/T2)^1/2
(C) ΔS<0 (C) 1-(T1/T2)^2

A rigid container is divided into 2 A steam engine operating between high

compartments of equal volume by a temperature T2 and low temperature T1,
partition. One compartment contains 1 mole which of the following will give the greater
ideal gas A at 1 atm, and the other contains increase in the efficiency of the engine:
1 mole of ideal gas B at 1 atm. What is ΔS if (A) an increase of ΔT in T2
both compartments had contained ideal gas (B) a decrease of ΔT in T1
A?
(A) ΔS>0 Consider the free expansion experiment of a
(B) ΔS=0 gas originally in the left chamber and is
(C) ΔS<0 allowed to expand into the right chamber of
equal volume when the separation is
In the Joule-Thomson expansion, which removed. Comparing the case of only 1
state function does not change? atom in the left chamber with that of 10
(A) U atoms in the left chamber, which system has
(B) S a larger entropy change?
(C) H (A) 1 atom
(B) 10 atoms
Under the condition of constant P and T, the
equilibrium state is determined by
examining which of the following state
functions?
(A) H
(B) G
(C) U
(D) S

Under the condition of constant P and T, the

equilibrium state corresponds to a
(A) maximum
(B) minimum of that function

Regular solutions are characterized by

G(XS) = α*Xa*Xb. When α < 0, phase
separation occurs.
True or False?
4
Quiz
Continue with Figure 1. Between the It was found in the homework problem that
compositions of Xb and Xd, what are the DG for the reaction Si3N4+3O2-
equilibrium conditions? >3SiO2+2N2 has a negative ΔG at 800K.
(A) Ḡ a(s) = Ḡ a(l) The reaction
(B) Ḡ b(s) = Ḡ b(l) (A) will
(C) Ḡ⁰ a(s) = Ḡ a(l) (B) will not, happen spontaneously
(D) Ḡ⁰ b(s) = Ḡ b(l)
Supercooled liquids are not stable with time.
The ΔGm of three liquid mixtures (I, II, III) If it is adiabatically contained, some of it
as a function of Xb is shown in Figure 2. will
Choose the liquid mixture that has the (A) freeze
largest activity aB at the composition Y of (B) evaporate, when it reaches equilibrium
the dashed line.
(A) I If the supercooled liquids is at T1 initially
(B) II and adiabatically contained, after it reaches
(C) III equilibrium, the final temperature is T2.
(A) T2>T1
The Gibbs Free Energy change of (B) T2=T1
completely miscible liquid solutions and (C) T2<T1
completely immiscible solids of component
A and component B is shown in Figure 3. The entropy of a substance in complete
What would be the free energy curve at internal equilibrium has
equilibrium? (A) S>0
(A) fbce (B) S=0
(B) fbcd (C) S<0 when T=0
(C) adce
(D) abcd The enthalpy of an element has
(A) H>0
Continue with Figure 3. Between the (B) H=0
compositions Xb and Xa (pure solid) what (C) H<0 when T=298 and P=1 atm
are the equilibrium conditions?
(A) Ḡ a(s) = Ḡ a(l)
(B) Ḡ b(s) = Ḡ b(l)
(C) Ḡ⁰ a(s) = Ḡ a(l)
(D) Ḡ⁰ b(s) = Ḡ b(l)

Continue with Figure 3. Between the

compositions Xc and Xd (pure solid) what
are the equilibrium conditions?
(A) Ḡ a(s) = Ḡ a(l)
(B) Ḡ b(s) = Ḡ b(l)
(C) Ḡ⁰ a(s) = Ḡ a(l)
(D) Ḡ⁰ b(s) = Ḡ b(l)
5
Quiz
The molar enthalpy of melting, Given the enthalpy change at the melting
ΔHm=ΔHliquid-ΔHsolid is point, ΔHm, and the melting temperature,
(A) positive Tm, we can calculate entropy change at the
(B) zero melting point.
(C) negative True or False?

The ΔH of carbon oxidation, that is the Activity component of A of any solution is

reaction of carbon with oxygen resulting in equal to its mole fraction Xa.
carbon monoxide, is True or False?
(A) positive
(B) zero Considering the figure for an A-B solution,
(C) negative in the range of Xb < 0.2, _____.
(A) Component A obey's Henry's Law
Select quantities below that do not change (B) Component A obeys Raoult's Law
after the formation of an ideal solution. (C) Component B obeys Henry's Law
(A) G (D) Component B obeys Raoult's Law
(B) H
(C) S
(D) V

We can calculate Gibbs Free Energy from

the knowledge of enthalpy but we cannot
calculate enthalpy from the knowledge of
Gibbs Free Energy.
True or False?

If a solution behaves as an ideal solution, the

gas above it will behave like an ideal gas.
True or False?

n moles of an ideal gas A and (1-n) moles of

an ideal gas B, each at 1 atm pressure, are
mixed at a constant total pressure. What
ratio of A to B in the mixture maximizes the
decrease in Gibbs Free Energy of the
system?
(A) 2:1
(B) 1:1
(C) 1:2

Select quantities below that do not change

after the mixing of two ideal gases.
(A) G
(B) H
(C) S
(D) V
6
Quiz
Boiling point of a liquid ____ when the Condensation of vapor occurs when the
ambient pressure decreases. temperature is lowered because the vapor
(A) increases pressure of the system becomes ____ than
(B) stays the same the equilibrium pressure.
(C) decreases (A) higher
(B) lower
ΔH(s to v) is generally _____ than ΔH(l to
v). The equilibrium vapor pressure of a liquid
(A) larger than ____ with increasing temperature.
(B) equal to (A) increases
(C) smaller than (B) stays the same
(C) decreases
The above behavior of G describes which
phase diagram given above? Which of the above phase diagrams
Choose A or B. corresponds to water?
Choose A or B.
Given a solid-vapor equilibrium equation
ln(P) = (-A/T) + C, and the triple point
temperature, we ____ predict the liquid-
vapor pressure equilibrium equation.
(A) can
(B) cannot

Given a solid-vapor equilibrium equation

ln(P) = (-A/T) + C, the difference in heat
capacities between solid and vapor can be
deduced to be ____.
(A) ΔCp(s to v) > 0
(B) ΔCp(s to v) = 0
(C) ΔCp(s to v) < 0

Given the equation ln(P) = (-A/T) + C, we

can calculate which state function below?
(A) ΔU
(B) ΔG
(C) ΔH
(D) ΔS

Given a phase diagram of (B) in the figure

above, applying pressure to a liquid can
____ the freezing temperature.
(A) increase
(B) maintain
(C) decrease
7
Quiz
Considering the figure above for an A-B The Gibbs Free Energy change of liquid
solution, we can deduce that A-B attraction solution and solid solution of completely
is ___ than the A-A and B-B attraction. miscible component A and component B is
(A) stronger shown in Figure 1. What would be the free
(B) the same energy curve at equilibrium?
(C) weaker (A) fcde
(B) abcg
The activites a(a) and a(b) of an A-B (C) abcde
solution are not independent of each other. (D) abde
True or False?
Maxwell's relations are mathematical
The adiabatic flame temperature of a fuel in relations resulting from
air is (A) First law
(A) higher than (B) Second law
(B) the same as (C) property of state functions
(C) lower than that in oxygen (D) Carnot theorem

2 mole of Al and 1 mole of Fe2O3 can react For regular solutions, the activity coefficient
to form 1 mole of Al2O3 and 2 moles of Fe γ > 1 for α > 0.
and release a large amount of heat. If True or False?
adiabatically contained, the released heat
can melt the For regular solutions with α > 0, ΔG is ____
(A) Al2O3 than that of ideal solutions
(B) Fe (A) larger
(B) the same as
Enthalpy of a system is a function of (C) smaller
temperature and pressure. The dependence
on temperature is
(A) stronger than
(B) the same as
(C) weaker than that on pressure

How many Maxwell's relations are there?

(A) 2
(B) 3
(C) 4
(D) 5