# Thermodynamics Test Review 1112x

Mechanics

Oct 27, 2013 (4 years and 6 months ago)

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Thermodynamics Test Review

1. Define endothermic.

2. What is

H for an endothermic reaction?

3. Define exothermic.

4. What is

H for an exothermic reaction?

5. Be able to calculate heat or specific heat using q=mc

T

a. How

much heat is released when 25 mL of water is heated 5
°
C. The specific heat of water is 4.184
J/g
°
C?

b. The temperature change of a 1.5
-
g sample of metal was 2.5
°

when that metal absorbed 675 kJ of
heat. Calculate the specific heat of the metal.

6. Understand entropy. When is

S positive and when is

S negative?

Determine

S for the following phase changes.

a. (l)

(g)

b. (g)

(s)

c. (s)

(aq)

d. (l)

(aq)

e. (l)

(s)

7.
Understand a potential energy diagram
and recognize if it is exothermic or endothermic.

8. Be

able to read and interpret a phase change diagram. Locate the freezing point, melting point,
boiling point, condensation point. Be able to determine when the substance is a solid, liquid, or a gas.

10.

What is

G for a nonspontaneous (needs energy) reaction?

11. What is

G for a spontaneous (releases energy) reaction?

12. Calculate

G using the equation

G=

H
-
T

S and the following data.

H =
-
68.5 kJ/mol

S = 95.2 J/mol K

T = 298 K

13. Be

able to calculate

H using the information below:

H kJ/浯l

Na(s)

0.0

H
2
O(l)

-
286

NaOH(aq)

-
470

H
2
(g)

0.0

Calculate

H for the following reaction:

2Na(s) + 2H
2
O(l)

2NaOH(aq) + H
2
(g)

14. The ΔH of N
2
O
5
(g) is to be determined using the
thermodynamic data shown below.

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

2H
2
O(l)

ΔH =
-
285.8 kJ/mol

2N
2
O
5
(g) + 2H
2
O(l)

4HNO
3
(l)

ΔH =
-
153.2 kJ/mol

N
2
(g) + 3O
2
(g) + H
2
(g)

2HNO
3
(l)

ΔH =
-
174.1 kJ/mol

Using the thermodynamic data above, determine the ΔH of for the

following reaction:

2N
2

+ 5O
2

2N
2
O
5

15.
Be able to solve:

A metal with a
mass of 12.2 grams and an initial temperature of 100.5
°
C is added to 25.0 grams of water
with an initial temperature of 23.5
°
C. After the metal was added, the temperature

of the water rose to
29.0
°
C. Calculate the specific heat of the metal. The specific heat of water is 4.184 J/g
°
C.