Advanced Chem Thermodynamics

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Question 1

What is the enthalpy of reaction?

C H OH(l) + 3O (g) 2CO (g) + 3H O(l)

H (C H OH(l)) -228 kJ/mol

H (CO (g)) -394 kJ/mol

H (H O(l)) -286 kJ/mol

Your Answer Score Explanation

158 kJ

-908 kJ

-452 kJ

-1418 kJ 1.00

Total 1.00 / 1.00

Question 2

Which process will result in a decrease in the entropy?


N O (g) 2NO (g)

H O(s) H O(l)

2 5 2 2 2

f 2 5

f 2

f 2

2 4 2

2 2



H O(s) H O(l)

NaCl(s) NaCl(aq)

CO (g) CO (s) 1.00

Total 1.00 / 1.00

Question 3

Which process will be spontaneous?


Sublimation of CO (s) at 1 atm and 25 1.00

Ice melting at -10

NaCl precipitating out of an unsaturated solution

2Fe O (s) 4Fe(s) + 3O (g)

Total 1.00 / 1.00

Question 4

What is S given S = 392 J/K and S = -184 J/K?


-208 J/K

208 J/K 1.00

-576 J/K

576 J/K

Total 1.00 / 1.00

2 2

2 2

2

2 3 2

univ sys surr



Question 5

What is S at 35C when H = 36 kJ/mol?


117 J/molK

1029 J/molK

-117 J/molK 1.00

-1029 J/molK

Total 1.00 / 1.00

Question 6

When H and S are both positive, what can be said about the spontaneity of the reaction?


Spontaneous at high temperatures because G is

negative.

1.00

Spontaneous at high temperatures because G is

positive.

Spontaneous at low temperatures because G is

negative.

Spontaneous at low temperatures because G is positive.

Total 1.00 /

1.00

surr sys



Question 7

Find G at 20C when H = 184 kJ and S = 432 J/K.


109 kJ

74.7 kJ 1.00

57.4 kJ

175 kJ

Total 1.00 / 1.00

Question 8

Predict which of the following substances will have the greatest molar entropy?


Ar (g)

B (s)

Cl (g) 1.00

CHCl (l)

Total 1.00 / 1.00

Question 9

Calculate the standard entropy change (S) for the reaction from the given standard entropies

provided in the table.

sys

12

2

3



C H (g) + 5 O (g) 3 CO (g) + 4 H O(g)

bgcolor="#ff6600">

Substance S(J/mol K)

C H (g) 270.3

O (g) 205.2

CO (g) 213.8

H O(g) 188.8


2155.3 J/K

100.3 J/K 1.00

-72.9 J/K

337.6 J/K

Total 1.00 / 1.00

Question 10

Which of the following is a chemical equation for the free energy for the formation of water?


2 H O(l) 2 H (g) + O (g)

H (g) + O (g) H O(l) 1.00

H (g) + O(g) H O(l)

2 H (g) + O (g) 2 H O(l)

Total 1.00 / 1.00

3 8 2 2 2

.

3 8

2

2

2

2 2 2

2 2 2

2 2

2 2 2



Question 11

Determine the standard free energy of formation (G ) for C H , given the following information.

All values were measured at 25 C.

C H (g) + 5 O (g) 3 CO (g) + 4 H O(g) G = -2074.2 kJ

bgcolor="#ff6600">

Substance G (kJ/mol)

CO (g) -394.4

H O(g) -228.6


-23.4 kJ/mol 1.00

-1451.2 kJ/mol

-2074.2 kJ/mol

117.0 kJ/mol

Total 1.00 / 1.00

Question 12

The following reaction is allowed to proceed and equilibrium is established. Which statement is

false?

C H (g) + 5 O (g) 3 CO (g) + 4 H O(g) G = -2074.2 kJ


When equilibrium is established, G = 0.0 kJ 1.00

f 3 8

3 8 2 2 2

f

2

2

3 8 2 2 2



If the reaction initially has one mole of each gas present in

the reaction chamber, the reaction will proceed toward

products to reach equilibrium.

When equilibrium is established, the partial pressures of

CO and H O will both be greater than the partial pressures of

C H and O .

When equilibrium is established, G = 0.0 kJ

Total 1.00 /

1.00

Question 13

Determine G at 25C for the following reaction based on the pressures given in the table.

C H (g) + 5 O (g) 3 CO (g) + 4 H O(g) G = -2074.2 kJ

bgcolor="#ff6600">

Substance P (atm)

C H (g) 10.0

O (g) 13.3

CO (g) 0.0100

H O(g) 0.0500


-2175.7 kJ 1.00

8.921 10 kJ

74.5 kJ

-2074.2 kJ

2 2

3 8 2

3 8 2 2 2

3 8

2

2

2

4



Total 1.00 / 1.00

Question 14

Determine K for the following reaction at 25C.

H (aq) + F (aq) HF(aq) G = -19.7 kJ


1.3 10

6.8 10

2.8 10 1.00

1.1

Total 1.00 / 1.00

c

+ -

41

-5

3

Advanced Chem Thermodynamics

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