Name ______________________________________________________ Date __________________ Period ______
Thermochemistry Worksheet
Chemistry; Coleman
Part One:
1. What is an endothermic reaction? (Explain what happens in terms of heat flow, and what happens to the
temperature of the surroundings)
2. What is an exothermic reaction? (Explain what happens in terms of heat flow, and what happens to the
temperature of the surroundings)
3. Label the following energy diagram:
a ______________________
b______________________
d
c______________________
d______________________
b
Part Two: For each of the following reactions, determine the answer the questions that follow:
4. CH4(g) + 2O2(g)  CO2(g) + 2H2O(g)
H = -890. kJ
a. Endothermic or exothermic? _______________________
b. Heat is released or absorbed?______________________
c. Temperature would go up or down? ________________
d. Rewrite the equation putting the heat in as a reactant or product:
e. Sketch an energy diagram for the reaction in the box to the right.
5. PbO(s) + C(s) + 106.8kJ  Pb(s) + CO(g)
a. Endothermic or exothermic? _______________________
b. Heat is released or absorbed?______________________
c. Temperature would go up or down? ________________
d. What is the enthalpy change (H) for this reaction?
e. Sketch an energy diagram for the reaction in the box to the right.
6. 2MgO(s)  2Mg (s) + O2 (g)
a.
b.
c.
d.
H = +72.3 kJ
Endothermic or exothermic? _______________________
Heat is released or absorbed?_______________________
Temperature would go up or down? ________________
Rewrite the equation putting the heat in as a reactant or product:
e. Sketch an energy diagram for the reaction in the box to the right.
7. 2Al + 3NH4NO3  3N2 + 6 H2O + Al2O3 + 2030kJ
a.
b.
c.
d.
Endothermic or exothermic? _______________________
Heat is released or absorbed?_______________________
Temperature would go up or down? ________________
What is the enthalpy change (H) for this reaction?
e. Sketch an energy diagram for the reaction in the box to the right.
8. 3NO2 + H2O  2HNO3 + NO
a.
b.
c.
d.
H = -138 kJ
Endothermic or exothermic? _______________________
Heat is released or absorbed?_______________________
Temperature would go up or down? ________________
Rewrite the equation putting the heat in as a reactant or product.
e. Sketch an energy diagram for the reaction in the box to the right.
9. CO2 (g) + 2H2O (l)  CH4 (g) + 2O2(g) H= +890.3 kJ
a.
b.
c.
d.
Endothermic or exothermic? _______________________
Heat is released or absorbed?_______________________
Temperature would go up or down? ________________
Rewrite the equation putting the heat in as a reactant or product.
e. Sketch an energy diagram for the reaction in the box to the right.
Part Three: State whether the following reactions are endothermic or exothermic:
10. Melting ______________________________
11. Evaporation ______________________________
12. Freezing ______________________________
13. Combustion ______________________________
14. Condensation ______________________________
15. Sublimation ______________________________
Part Four: Answer the questions that follow each energy diagram:
16. What are the reactants?
17. What are the products?
18. What would the chemical equation for this
reaction be?
19. How much activation energy is required for this reaction? (show your work)
20. What is the enthalpy change (∆H) for this reaction? (show your work)
21. Is the overall reaction as shown above exothermic or endothermic? How do you know?
22. What are the reactants?
23. What are the products?
24. What would the chemical equation for this reaction
be?
25. How much activation energy is required for this reaction? (show your work)
26. What is the enthalpy change (∆H) for this reaction? (show your work)
27. Is the overall reaction as shown above exothermic or endothermic? How do you know?
(There is more on the back…)
28. What are the reactants?
29. What are the products?
30. What would the chemical equation for this reaction be?
31. What is the enthalpy change (∆H) for this reaction?
32. Is the overall reaction as shown above exothermic or endothermic? How do you know?