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Thermochemistry Test

Total questions: 12

Worksheet time: 6mins

Name
Class
Date
1.

A piece of metal is heated, and then submerged in cool water. Which statement below describes the best what happens?

a)

The temperature of the metal will increase

b)

The temperature of the water will increase

c)

The temperature of the water will decrease

d)

The temperature of the water will increase and the temperature of the metal will decrease

2.

Calculate ΔH for the following reaction:

C2H4(g) + H2(g) → C2H6(g) ΔHC2H4(g) = 52.5 kJ/mol ΔHC2H6(g) = -84.7 kJ/mol

a)

-32.2 kJ/mol

b)

32.2 kJ/mol

c)

137.2 kJ/mol

d)

-137.2 kJ/mol

3.

Which statement is true for the combustion of ethanol?

C2H5OH(l) + 3O2(g) → 2CO2(g) + 3H2O(l) ΔH = -1370 kJ

a)

The potential energy of the products is less than the potential energy of the reactants.

b)

The reaction is endothermic.

c)

The potential energy of the products is more than the potential energy of the reactants.

d)

None of the statements above are correct.

4.

What is the amount of heat required to raise the temperature of 200.0 g of aluminum by 11°C? (CAl = 0.21 cal/g°C)

a)

460 cal

b)

460 J

c)

462 cal

d)

462 J

5.

All of the following have ΔHf° = 0.0 kJ/mol EXCEPT:

a)

O2(g)

b)

Ca(s)

c)

Br2(l)

d)

Hg(l)

6.

During interval DE, which energy change occurs for the particles in this sample?

a)

The potential energy of the particles decreases

b)

The potential energy of the particles increases

c)

The average kinetic energy of the particles increases

d)

The average kinetic energy of the particles decreases

7.

What happens to the substance during interval BC?

a)

IMF are decreasing and the substance is melting

b)

IMF are decreasing and the substance is freezing

c)

IMF are increasing and the substance is melting

d)

IMF are increasing and the substance is freezing

8.

Systems in nature tend to undergo changes toward

a)

Lower enthalpy and higher entropy

b)

Lower enthalpy and lower entropy

c)

Higher enthalpy and higher entropy

d)

Higher enthalpy and lower entropy

9.

Given the following two reactions:

C(s) + O2(g) → CO2(g)                     ∆H = -393.5 kJ

2Fe(s) + 3/2 O2(g) → Fe2O3(s)     ∆H = -824.2 kJ

Calculate the enthalpy change for:

2Fe2O3(s) + 3C(s) → 4Fe(s) + 3CO2(g)

a)

-467.9 kJ

b)

-430.7 kJ

c)

467.9 kJ

d)

430.7 kJ

10.

Which of the following represents an increase in entropy?

a)

freezing of water

b)

boiling of water

c)

crystallization of salt from a solution

d)

2 NO(g) → N2O2(g)

11.

For any reaction at equilibrium, which of the following is true?

a)

ΔH < 0

b)

ΔS = 0

c)

ΔS < 0

d)

ΔG = 0

12.

Which diagram represents the potential energy changes during an endothermic reaction?

a)

Diagram a

b)

Diagram b

c)

Diagram c

d)

Diagram d