QUIZ #7
SC112,Spring2016
Prof. M. Elert
NAME
!<'EY
I1GO =-RTlnK
R = 8.314 llmol K
I.
(2 points) If I1H<O and I1S>O for a reaction, the reaction will
proceed spontaneously to the right at all temperatures.
proceed spontaneously to the right only at high temperatures.
c. never proceed spontaneously to the right.
d. proceed spontaneously to the right only at low temperatures.
2. (2 points) Which of the following is consistent with a reaction that proceeds spontaneously in the forward
direction?
.
e. I1G > 0 and Q < K
f. I1Go = 0 and Q = K
..k I1G < 0 and Q > K
UY I1G < 0 and Q < K
1. I1Go > 0 and Q < K
3. (2 points) The normal boiling point of water is 100°C and 1 atm pressure. At 110°C and I atm pressure, the
following can be predicted about I1Ho, I1Go, and I1So of vaporization:
o
I1HO > 0, I1GO < 0, and I1So > 0
b. I1Ho > 0, I1Go >0, and I1So >0
c. I1Ho < 0, I1Go < 0, and I1So < 0
d. I1HO < 0, I1Go > 0, and I1So < 0
4. (2 points) Predict whether the entropy change will be positive or negative for each of the following reactions:
31.0 kJ/mol and
5. (3 points) For the vaporization of bromine (that is, for the reaction Br2(l) --7 Br2(g) ) I1Ho
I1So = 93.0 J/mol·K. Calculate the approximate boiling point of bromine.
6. r; -=- 0 -::- L.i t/-
T A5
.D)-I::: fbS
3/000 J/~
<13.0 J/~;G
­
3~3 f<
-
......
60 "c
6. Relevant thennodynamic data at 25°C for the reaction 2PbO(s) + C(s)
LlHfo (kJ/mol)
Pb(s)
PbO(s)
C(s)
C02(g)
~
2Pb(s) + C02(g) is shown below:
So (J/K-mol)
64.9 68.7 5.7 213.6 0
-217.3
0
-393.5
a. (3 points) Calculate LlSO for the reaction above at 25°C.
bS°.::- 1-l6£f;t]) + 2(3.( - L-(6~.7) - C~7) ~ <..,06 .. 3
T/K
b. (3 points) Calculate LlGo for the reaction above at 25°C.
b. (1" ":.
- 393. S- -- L ( -
l-t 1.
3) -;.. ¥-I, i ,.lJ
/).,~::=. 6.{{~- T .6So::: q.{./ - (Z7E')Gz,(103) -;:; - {g.G'
7. (3 points) For the reaction N2(g) + 3 H2(g) ~ 2NHs(g) at 25°C, Kp = 6.6
Calculate Kp for this reaction at 200°C.
I<:L )
!. ( 1<;?
- .6(ll
<jL
(l-l-y -- J--)
~
-
..".,;-'
(
,)
L9g
-
•• > "
,
.. -­
'.
X
105 and LlHo = -92.6 kJ.
t-J