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Chapter 19: Gibbs,Entropy, and Eqm

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 1. 
The first law of thermodynamics can be given as __________.
a.
DE = q + w
b.
mc001-1.jpg
c.
for any spontaneous process, the entropy of the universe increases
d.
the entropy of a pure crystalline substance at absolute zero is zero
e.
DS = qrev/T at constant temperature
 

 2. 
A reaction that is spontaneous as written __________.
a.
is very rapid
b.
will proceed without outside intervention
c.
is also spontaneous in the reverse direction
d.
has an equilibrium position that lies far to the left
e.
is very slow
 

 3. 
When a system is at equilibrium, __________.
a.
the reverse process is spontaneous but the forward process is not
b.
the forward and the reverse processes are both spontaneous
c.
the forward process is spontaneous but the reverse process is not
d.
the process is not spontaneous in either direction
e.
both forward and reverse processes have stopped
 

 4. 
The thermodynamic quantity that expresses the degree of disorder in a system is __________.
a.
enthalpy
b.
internal energy
c.
bond energy
d.
entropy
e.
heat flow
 

 5. 
Which one of the following is always positive when a spontaneous process occurs?
a.
DSsystem
b.
DSsurroundings
c.
DSuniverse
d.
DHuniverse
e.
DHsurroundings
 

 6. 
The second law of thermodynamics states that __________.
a.
DE = q + w
b.
DH°rxn = S nDH°f (products) - S mDH°f (reactants)
c.
for any spontaneous process, the entropy of the universe increases
d.
the entropy of a pure crystalline substance is zero at absolute zero
e.
DS = qrev/T at constant temperature
 

 7. 
The normal boiling point of water is 100.0°C and its molar enthalpy of vaporization is 40.67 kJ/mol. What is the change in entropy in the system in J/K when 39.3 grams of steam at 1 atm condenses to a liquid at the normal boiling point?
a.
88.8
b.
-88.8
c.
-238
d.
373
e.
-40.7
 

 8. 
DS is positive for the reaction __________.
a.
2H2 (g)  +  O2 (g) ® 2H2O (g)
b.
2NO2 (g) ® N2O4 (g)
c.
CO2 (g) ® CO2 (s)
d.
BaF2 (s) ® Ba2+ (aq)  +  2F- (aq)
e.
2Hg (l)  +  O2 (g) ® 2HgO (s)
 

 9. 
The standard Gibbs free energy of formation of __________ is zero.

(a)  H2O (l)
(b)  Na (s)
(c)  H2 (g)
a.
(a) only
b.
(b) only
c.
(c) only
d.
(b) and (c)
e.
(a), (b), and (c)
 

 10. 
For the reaction

C2H6 (g) ® C2H4 (g)  +  H2 (g)

DH° is +137 kJ/mol and DS° is +120 J/K • mol. This reaction is __________.
a.
spontaneous at all temperatures
b.
spontaneous only at high temperature
c.
spontaneous only at low temperature
d.
nonspontaneous at all temperatures
 

 11. 
A reaction that is not spontaneous at low temperature can become spontaneous at high temperature if DH is __________ and DS is __________.
a.
+, +
b.
-, -
c.
+, -
d.
-, +
e.
+, 0
 

 12. 
If DG° for a reaction is greater than zero, then __________.
a.
K = 0
b.
K = 1
c.
K > 1
d.
K < 1
e.
More information is needed.
 



 
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