Honors Chemistry
Name: ______________________________________ Date: ________________ Mods: __________
Chapter 5: Thermochemistry
Objectives: the student will be able to:
 Define energy and the units used in measuring energy.
o Kinetic energy
o Potential energy
o Joule
 Understand and apply the first law of thermodynamics
o Define Internal energy, and state functions
o Relate ∆E to heat (q) and work (w)
o Understand the difference between endothermic and exothermic
o Perform calculations for change in energy (∆E)
 Define enthalpy (H) and apply enthalpy calculations to chemical reactions
o Calculate enthalpy of reactions.
o Use thermochemical reactions and enthalpy diagrams to calculate the enthalpy of a
reaction.
 Understand heat flow in a chemical reaction as measured by Calorimetry
 Apply an understanding of Hess’s Law to enthalpy calculations.
 Calculate enthalpies of formation for the formation of a compound
--------------------------------------------------------------------------------------------------------------------------------------Problem Sets: You are not limited to these problems but these are suggested problem sets in which
you can check your answer in the back of the textbook.
Pg. 205:
Pg. 206:
Pg. 207:
Pg. 208:
Pg. 209:
Pg. 209:
11, 17, 19, 20 (nature of energy)
23, 29 (first law of thermodynamics)
33, 35, 37, 39, 43, 45 (enthalpy)
47, 49, 51, 55, 57 (calorimetry)
59, 61, 63 (Hess’s Law)
65, 67, 69, 71 (enthalpies of formation)
Chapter 5: Thermochemistry – Vocabulary
1. Calorimetry -
2. Calorimeter -
3. Endothermic process -
4. Exothermic process -
5. Energy -
6. Enthalpy –
7. Enthalpy of Formation -
8. First Law of Thermodynamics –
9. Force -
10. Heat -
11. Hess’s Law -
12. Internal energy -
13. Kinetic energy –
14. Potential energy -
15. Specific heat capacity -
16. State function -
17. Surrounding -
18. System -
19. Thermochemistry -
20. Work -
Chapter 5: Thermochemistry - Outline
5.1 - The Nature of Energy
1. What is energy; how does it relate to chemical reactions? (*hint- electrostatic potential
energy)
2. What determines the chemical energy of a substance?
3. What is the SI unit of measure for energy? What are other common units used to
measure energy and how are they related?
4. Define the relationship of system and surrounding as it relates to heat transfer.
5.2 - The First Law of Thermodynamics
1. Explain how both a positive and negative value of ΔE result and what each value
indicates.
2. What is the relationship between internal energy (ΔE), heat (q) and work (w) –give
equation and fill in Table 5.1?
Equation:
For q
For w
For
ΔE
3. Describe endothermic as it relates to system/surroundings.
4. Describe exothermic as it relates to system/surroundings.
5. What does the value of a state function depend on?
5.3 - Enthalpy
1. Define enthalpy (H) and change in enthalpy (ΔH).
2. Indicate the meaning of both (-/+) ΔH.
5.4 - Enthalpy of Reaction
1. What is enthalpy of reaction? Include a formula in your definition.
2. Explain the purpose/properties of an enthalpy diagram.
3. Draw the example enthalpy diagram from Figure 5.16 and explain ΔH for a reverse reaction.
4. Identify the three basic guidelines for thermochemical equations and enthalpy
diagrams.
5.5 - Calorimetry
1. Give the equation for specific heat and label each variable.
2. What is the significance of the following equation: q = (s)(m)(ΔT)? [aka: q = mCp ΔT]
3. What is the difference between constant pressure and bomb calorimetry?
5.6 - Hess’s Law
1. What are the applications of Hess’s law in studying chemical reactions?
5.7 - Enthalpies of Formation
1. What is the standard enthalpy of formation?
2. How can we use standard enthalpy change to study enthalpy of reactions?
5.8 – Foods and Fuels
1. Where does most of the energy our bodies need come from?
2. Why are fats well suited to serve as the body’s energy reserve?
3. Compare the average fuel value of carbohydrates, fats, and proteins.
4. Discuss the total energy consumption of the US with respect to the rest of the world.
5. Name and describe 3 fossil fuels.
6. How is nuclear energy obtained? Like fossil fuels, it is a _______________ source of energy.
7. Name and describe the 5 renewable energy sources discussed in this chapter.