thermo report
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Neumann University *
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Course
107
Subject
Chemistry
Date
Jan 9, 2024
Type
docx
Pages
4
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Experiment: Thermodynamics
Abstract
Introduction
Objective
Conclusions
Page 1
of 4
e8d0cffca44dabff42cd565c13ea1a59cb4b0451.docx
Copyright © 2020-2021 RCSJ, All rights reserved.
Experiment: Thermodynamics
Data and Results
B.
Question 1: Predict the Sign of ∆ S
rxn
o
.
For each of the reactions listed in Table 3, predict the sign of D
S
o
. Use the cases and examples in the introduction to help. Based on the predictions, record either + or – in the chart below. Explain how the prediction was made.
Reactions
Predicted
Sign (+ or -) of
D
S
Explanation
N
2
(g) + 2O
2
(g) --> 2 NO
2
(g)
N
2
O (g) + NO
2
(g) à
3NO(g)
6Cl
2
(g) + 2Fe
2
O
3
(s) à
4FeCl
3
(s) + 3O
2
(g)
SO
2
(g) + 2H
2
(g) à
S(s) + 2H
2
O(g)
3 Fe2O
3
(s) + H
2
(g) --> 2Fe
3
O
4
(s) + H
2
O(l)
P
4
O
10
(s) + 16H
2
(g) à
4PH
3
(g) + 10H
2
O(g)
2H
2
O
2
(l) à
2H
2
O(l) + O
2
(g)
C
. Table 4: Lab Data (Template—Copy into Excel)
Reactions
D
H
o
rxn
D
G
o
rxn
D
S
o
rxn
D
G
o
rxn @ 298K
D
G
o
rxn @ 10K D
G
o
rxn @ 10,000K
N
2
(g) + 2O
2
(g)
2 NO
2
(g)
N
2
O (g) + NO
2
(g) à
3NO(g)
6Cl
2
(g) + 2Fe
2
O
3
(s) à
4FeCl
3
(s) + 3O
2
(g)
SO
2
(g) + 2H
2
(g) à
S(s) + 2H
2
O(g)
3 Fe2O
3
(s) + H
2
(g)
2Fe
3
O
4
(s) + H
2
O(l)
P
4
O
10
(s) + 16H
2
(g) à
4PH
3
(g) + 10H
2
O(g)
2H
2
O
2
(l) à
2H
2
O(l) + O
2
(g)
D. Calculate
∆ H
rxn
o
∆G
rxn
o
, , and ∆ S
rxn
o
.
(Use Excel and Table 1)
E. Calculate ∆G
rxn
o
at 298 K
. (Use Excel and Equation 2: ∆G
rxn
o
=
∆ H
rxn
o
−
T ∆S
rxn
o
)
Page 2
of 4
e8d0cffca44dabff42cd565c13ea1a59cb4b0451.docx
Copyright © 2020-2021 RCSJ, All rights reserved.
F
. Question 3. ∆G
rxn
o
was calculated using two different methods, are the values similar? Explain.
Experiment: Thermodynamics
G.
Question 2: Exo- or Endothermic, Ender- or Exergonic, Spontaneous/Non-Spontaneous
Answer the following questions in the chart below.
1.
Examine the values found for Enthalpy. Which reactions are endothermic, and which are exothermic?
2.
Examine the values found for Gibb’s Free energy, ∆G
rxn
o
. Which reactions are endergonic, and which are exergonic at 298K?
3.
At 298K, which reactions are spontaneous, and which are nonspontaneous?
Reactions
Exothermic or Endothermic
Exergonic or Endergonic at 298K
Spontaneous or Non-spontaneous at 298K
Entropy predictions match calculations?
(Yes or No)
N
2
(g) + 2O
2
(g)
2 NO
2
(g)
N
2
O (g) + NO
2
(g) à
3NO(g)
6Cl
2
(g) + 2Fe
2
O
3
(s) à
4FeCl
3
(s) + 3O
2
(g)
SO
2
(g) + 2H
2
(g) à
S(s) + 2H
2
O(g)
3 Fe2O
3
(s) + H
2
(g)
2Fe
3
O
4
(s) + H
2
O(l)
P
4
O
10
(s) + 16H
2
(g) à
4PH
3
(g) + 10H
2
O(g)
2H
2
O
2
(l) à
2H
2
O(l) + O
2
(g)
4.
a. Did the predictions made in question 1 about entropy match the calculations? Type yes or no in the chart below. H. Question 4: Temperature and Spontaneity
Reactions
Spontaneous at all T
Non-spontaneous at all T
Spontaneous at high T
Spontaneous at low T
N
2
(g) + 2O
2
(g)
2 NO
2
(g)
N
2
O (g) + NO
2
(g) à
3NO(g)
6Cl
2
(g) + 2Fe
2
O
3
(s) à
4FeCl
3
(s) + 3O
2
(g)
SO
2
(g) + 2H
2
(g) à
S(s) + 2H
2
O(g)
3 Fe2O
3
(s) + H
2
(g)
2Fe
3
O
4
(s) + H
2
O(l)
P
4
O
10
(s) + 16H
2
(g) à
4PH
3
(g) + 10H
2
O(g)
2H
2
O
2
(l) à
2H
2
O(l) + O
2
(g)
1.
Use the signs of ∆ H
rxn
o
and ∆ S
rxn
o
to predict how temperature will affect spontaneity for each reaction listed. Use Table 2 to determine into which category each reaction falls. For each reaction, type one of the following into the chart: spontaneous at all T, non-spontaneous at all T,
spontaneous at high T, spontaneous at low T)
2.
Calculate ∆G
rxn
o
at 10 K (low temp) and 10,000 K (high temp).
Use Excel and equation 2:
∆G
rxn
o
=
∆ H
rxn
o
−
T ∆S
rxn
o
Page 3
of 4
e8d0cffca44dabff42cd565c13ea1a59cb4b0451.docx
Copyright © 2020-2021 RCSJ, All rights reserved.
b. If entropy predictions did not match the calculations, explain what could have caused the discrepancy.
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Experiment: Thermodynamics
Excel
Data Table Excel Data Table with Formulas Page 4
of 4
e8d0cffca44dabff42cd565c13ea1a59cb4b0451.docx
Copyright © 2020-2021 RCSJ, All rights reserved.
I.
Question 5:
∆G
rxn
o
at High and Low Temperatures—Predicted vs Calculated.
Do the calculations for ∆G
rxn
o
at high (10,000 K) and low (10 K) temperatures match the predictions made in question 4? Explain.