UNIT 6 STUDY GUIDE: THERMOCHEMISTRY
You may either:
(1) Complete this study guide on a SEPARATE SHEET OF PAPER, and submit on the day of the test for up to 10
pts EC on the test. (I will be checking it for accuracy.)
(2) Forfeit the EC, and then use this study guide as an aid on the test. However, there is to be no sharing of study
guides!!
Define:
 Activation Energy
 Free energy
 Specific heat
 Calorimeter
 Heat
 Sublimation
 Condensation
 Heat of combustion
 Temperature
 Endothermic
 Heat of formation
 Thermochemistry
 Enthalpy
 Heat of fusion
 Vaporization
 Entropy
 Heat of vaporization
 Exothermic
 Joule
Questions:
1. Dropping a hot piece of metal into 50 g of water causes the temperature of the water to increase by 2.5C. How much
heat was absorbed by the water? What equation do you need to use to determine the answer?
2. How can Hess’ Law be used to find the Hrxn from Hf values? From other Hrxn values?
3. What is true for the Hf of all elements?
4. How much heat is required to vaporize 72 g of water (Hvap = 40.7 kJ/mol)?
5. The burning of 0.500 moles of carbon to form carbon dioxide releases 197 kJ of heat. How much heat is released
when 1.00 mole of CO2 is produced in a similar reaction?
C (s) +O2 (g)  CO2 (g)
6. What information does the sign on H give you? The sign on S? G?
7. In the table below, indicate whether the combination of H, S and T will result in a spontaneous or
nonspontaneous reaction.
High Temperature
Low Temperature
+H, +S
+H, -S
-H, +S
-H, -S
8. Predict the sign of S in each of the following:
a) Fe (s)  Fe (l) b) 2 H2 (g) + O2 (g)  2 H2O (g)
c) CO2 (s)  CO2 (g)
9. What is the equation for calculating the free energy change in
a reaction? What is something you should be careful of when
doing calculations with enthalpy and entropy values?
10. What arrows in the diagram at right correspond to the
activation energy, heat of reaction, and enthalpy of the
products?
11. What is true about temperature during a phase change?
12. Sketch a heating curve for a substance that melts at -20C
and boils at 50C. Label the phases that are present at each
interval.
13. How are volume and shape described for solids, liquids and
gases in terms of the particles in them?