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If a reaction is nonspontaneous at 298 K with a negative ΔHo, then the reaction…
Related Topics
Wize High School Grade 12 Chemistry Textbook > Energy Changes
Introduction to Thermochemistry
2 Activities
If a reaction is nonspontaneous at 298 K with a negative ΔH
o
, then the reaction is:
Select all that apply
Nonspontaneous at all temperatures.
Nonspontaneous at all temperatures higher than 298 K.
Spontaneous at some temperature lower than 298 K.
Nonspontaneous only at that temperature.
We need some more data regarding the entropy.
I don't know
Check Submission
More Introduction to Thermochemistry Questions:
Which of the following is an Intensive Property?
Gibbs Free Energy
The reaction of
H
2
(
g
)
+
C
O
2
(
g
)
↔
H
2
O
(
g
)
+
C
O
(
g
)
a
t
2000
K
K
P
=
4.40
H_{2(g)}+CO_{2(g)}\leftrightarrow H_2O_{(g)}+CO_{(g)}\ at\ 2000K\ K_P=4.40
H
2
(
g
)
+
C
O
2
(
g
)
↔
H
2
O
(
g
)
+
C
O
(
g
)
a
t
2000
K
K
P
=
4.40
Calculate ΔG for this reaction
Thermochemistry: Temperature
The oxidation of NO is shown below. Using the provided thermodynamic data answer the following questions
2
N
O
(
g
)
+
O
2
(
g
)
→
2
N
O
2
)
g
)
2\ NO_{(g)}+O_{2(g)}\rightarrow2\ NO_{2)g)}
2
N
O
(
g
)
+
O
2
(
g
)
→
2
N
O
2
)
g
)
Δ
H
o
=
−
57.1
k
J
m
o
l
and
Δ
S
o
=
−
73
J
m
o
l
a
t
298
K
\Delta H^o=-57.1\frac{kJ}{mol}\ \text{and}\ \Delta S^o=-73\frac{J}{mol}\ at\ 298K
Δ
H
o
=
−
57.1
m
o
l
k
J
and
Δ
S
o
=
−
73
m
o
l
J
a
t
298
K
Thermochemistry: Gibbs Free Energy
The oxidation of NO is shown below. Using the provided thermodynamic data answer the following questions
2
N
O
(
g
)
+
O
2
(
g
)
→
2
N
O
2
)
g
)
2\ NO_{(g)}+O_{2(g)}\rightarrow2\ NO_{2)g)}
2
N
O
(
g
)
+
O
2
(
g
)
→
2
N
O
2
)
g
)
Δ
H
o
=
−
57.1
k
J
m
o
l
and
Δ
S
o
=
−
73
J
m
o
l
a
t
298
K
\Delta H^o=-57.1\frac{kJ}{mol}\ \text{and}\ \Delta S^o=-73\frac{J}{mol}\ at\ 298K
Δ
H
o
=
−
57.1
m
o
l
k
J
and
Δ
S
o
=
−
73
m
o
l
J
a
t
298
K
Thermochemistry: Equilibrium (Keq)
The Haber Bosch Process is an industrial process for “fixing” nitrogen, shown below.This process produces around 500 million tons of ammonia every year. Calculate K
eq
3
H
2
(
g
)
+
N
2
(
g
)
→
2
NH
3
(
g
)
3\ H_{2(g)}+N_{2(g)}\rightarrow\ 2\ \text{NH}_{3(g)}
3
H
2
(
g
)
+
N
2
(
g
)
→
2
NH
3
(
g
)
Δ
f
G
o
(
N
H
3
)
=
−
16.4
k
J
/
m
o
l
\Delta _fG^o(NH_3)=-16.4\ kJ/mol
Δ
f
G
o
(
N
H
3
)
=
−
16.4
k
J
/
m
o
l
Using the following data, calculate the standard entropy change for the reaction:
2
A
l
(
s
)
+
3
Z
n
O
(
s
)
→
A
l
2
O
3
(
s
)
+
3
Z
n
(
s
)
2Al_{(s)}+3ZnO_{(s)}\to Al_2O_{3(s)} +3Zn_{(s)}
2
A
l
(
s
)
+
3
Z
n
O
(
s
)
→
A
l
2
O
3
(
s
)
+
3
Z
n
(
s
)
Report your answer in J/mol K to four significant figures. Do not include units in the answer field.
A spontaneous process:
Which of the following statements regarding spontaneous changes is
false
?
A freshly baked pie is placed near an open window to cool. Which of the following statements best describes this situation?
Thermodynamics: Heat and Work
Consider the following balanced chemical equation for the combustion of propane, C
3
H
8
:
C
3
H
8
(
g
)
+
5
O
2
(
g
)
→
4
H
2
O
(
ℓ
)
+
3
C
O
2
(
g
)
q
<
0
C_3H_8 (g) + 5 O_2 (g) → 4 H_2O (ℓ) + 3 CO_2 (g) \qquad q < 0
C
3
H
8
(
g
)
+
5
O
2
(
g
)
→
4
H
2
O
(
ℓ
)
+
3
C
O
2
(
g
)
q
<
0
Use this information to answer the next two questions. Choose one if the options inside the brackets
The oxidation of NO is shown below. Using the provided thermodynamic data answer the following questions
2
N
O
(
g
)
+
O
2
(
g
)
→
2
N
O
2
)
g
)
2\ NO_{(g)}+O_{2(g)}\rightarrow2\ NO_{2)g)}
2
N
O
(
g
)
+
O
2
(
g
)
→
2
N
O
2
)
g
)
Δ
H
o
=
−
57.1
k
J
m
o
l
and
Δ
S
o
=
−
73
J
m
o
l
a
t
298
K
\Delta H^o=-57.1\frac{kJ}{mol}\ \text{and}\ \Delta S^o=-73\frac{J}{mol}\ at\ 298K
Δ
H
o
=
−
57.1
m
o
l
k
J
and
Δ
S
o
=
−
73
m
o
l
J
a
t
298
K
The oxidation of NO is shown below. Using the provided thermodynamic data answer the following questions
2
N
O
(
g
)
+
O
2
(
g
)
→
2
N
O
2
)
g
)
2\ NO_{(g)}+O_{2(g)}\rightarrow2\ NO_{2)g)}
2
N
O
(
g
)
+
O
2
(
g
)
→
2
N
O
2
)
g
)
Δ
H
o
=
−
57.1
k
J
m
o
l
and
Δ
S
o
=
−
73
J
m
o
l
a
t
298
K
\Delta H^o=-57.1\frac{kJ}{mol}\ \text{and}\ \Delta S^o=-73\frac{J}{mol}\ at\ 298K
Δ
H
o
=
−
57.1
m
o
l
k
J
and
Δ
S
o
=
−
73
m
o
l
J
a
t
298
K
Find ΔG
0
for the following reaction.
CH
4
(
g
)
+
2
O
2
(
g
)
→
2
H
2
O
(
g
)
+
CO
2
(
g
)
\text{CH}_{4(g)}+2\ O_{2(g)}\rightarrow 2\ H_2O_{(g)}+\text{CO}_{2(g)}
CH
4
(
g
)
+
2
O
2
(
g
)
→
2
H
2
O
(
g
)
+
CO
2
(
g
)
Consider the following vaporization:
C
H
3
C
H
2
O
H
(
l
)
→
C
H
3
C
H
2
O
H
(
g
)
CH_3CH_2OH_{(l)}\to CH_3CH_2OH_{(g)}
C
H
3
C
H
2
O
H
(
l
)
→
C
H
3
C
H
2
O
H
(
g
)
If ∆H
vap
= 39.3 kJ/mol and the boiling point of ethanol is 78.3°C, what is ΔS for the vaporization of 1.73 mols of ethanol at its boiling point?
Predict the sign of the ΔH, ΔS,(+ or -) and identify when the following reactions are spontaneous at low temperature, high temperature, or all temperatures (low, high, all). Use commas to write your answers ie. +,+,low
For freezing of a popsicle: ΔH is ___________, ΔS is ___________. Reaction is spontaneous at ____________________ temperatures
For evaporation of liquid water: ΔH is ___________, ΔS is ___________. Reaction is spontaneous at ____________________ temperatures
Arrange the following compounds in order of increasing entropy, assuming 1 mol of each compound:
A
r
(
g
)
F
e
(
s
)
C
H
3
C
H
2
C
H
3
(
g
)
H
O
C
H
2
C
H
2
C
H
2
O
H
(
l
)
Ar(g) \hspace{15pt}Fe(s)\hspace{15pt} CH_3CH_2CH_{3(g)} \hspace{15pt} HOCH_2CH_2CH_2OH_{(l)}
A
r
(
g
)
F
e
(
s
)
C
H
3
C
H
2
C
H
3
(
g
)
H
O
C
H
2
C
H
2
C
H
2
O
H
(
l
)
A
r
(
g
)
Ar(g)
A
r
(
g
)
Calculate ΔS
sys
ΔS
surr
and ΔS
Univ
for the combustion of hydrogen shown below (unbalanced). Is the process spontaneous?
H
2
(
g
)
+
O
2
(
g
)
→
H
2
O
(
g
)
H_{2(g)}+O_{2(g)}\rightarrow H_2O_{(g)}
H
2
(
g
)
+
O
2
(
g
)
→
H
2
O
(
g
)
ΔH
f
0
(H
2
O
(g)
) = -285.83 kJ/mol
Thermochemistry: Entropy Calculations
Using the ΔH
0
of fusion for water 6.03 kJ/mol and the ΔS
0
of fusion for water 22.1 J K
-1
mol
-1
, calculate the ΔS
univ
for ice melting at -10
o
C, 0
o
C and 10
o
C. Remember: the universe transfers heat in a reversible way.
Thermodynamics: Entropy Calculations
Using the following data, calculate the standard entropy of the reaction shown below. Enter your answer in units of J / (mol*K)
2
A
l
(
s
)
+
3
Z
n
O
(
s
)
→
A
l
2
O
3
(
s
)
+
3
Z
n
(
s
)
2\ Al_{(s)}+3\ ZnO_{(s)}\rightarrow Al_2O_{3(s)}+3Zn_{(s)}
2
A
l
(
s
)
+
3
Z
n
O
(
s
)
→
A
l
2
O
3
(
s
)
+
3
Z
n
(
s
)
S
o
(
A
l
(
s
)
)
=
28.3
J
m
o
l
−
1
K
−
1
S^o(Al_{(s)})=28.3\ J\ mol^{-1}K^{-1}
S
o
(
A
l
(
s
)
)
=
28.3
J
m
o
l
−
1
K
−
1