Phases of Matter and Thermochemistry Review Sheet


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Chapter 9

  1. State the kinetic theory of gases.
  2. What causes gas pressure?
  3. Convert: a) 456 mm Hg to kPa b) 3.750 atm to kPa c) -125°C to K
  4. Explain why evaporation is a cooling process.
  5. Define allotrope, give 2 examples.

    Use the following phase diagram to answer questions 6-8. Show your answer on the diagram.
    Phase Diagram

  6. Label the solid, liquid, and vapor regions.
  7. What is the boiling point of the substance at 1 atm pressure?
  8. What state is a substance in if its temperature is 127°C at a pressure of 1.5 atm?
  9. Understand the meaning of figure 9.5 on p.242.
  10. What are intermolecular forces? How do they play a part in determining the boiling point of a substance?
  11. Explain why water boils at a lower temperature here than at sea level. Include the definition of boiling point.



Chapter 10
You will have to use pp. 266 and 276 for constants for various problems.

  1. How much heat, in joules, is required to raise the temperature of 45.0 mL of water from 14.0 °C to 48.0 °C?
  2. a) How much energy, in calories and in joules, is required to warm 197.25 g of grain alcohol (ethanol) from 22.0 °C to 37.0 °C?
    b) Would the same amount of water require less, more, or the same amount of heat? Explain.
  3. How much heat is required to boil 76 grams of water?
  4. A 120.0 gram piece of ice is removed from a refrigerator at -11.0 °C, placed in a glass, allowed to melt, and finally warmed up to room temperature, 21.0 °C. How much heat has the final water absorbed from the atmosphere?
  5. How much heat will be released in burning 78.4 g of C2H4? DH = -1390 kJ for the combustion reaction.
  6. Calculate DHrxn for each of the following reactions, using the H°f found in appendix A, table A.6 in the book.
    a) 2 NO(g) + O2(g) --> 2 NO2(g)
    b) Fe2O3(s) + 3 CO(g) --> 2 Fe(s) + 3 CO2(g)
  7. Given: MnO2(s) --> MnO(s) + 1/2 O2(g) DH = +32.5 kcal
    MnO2(s) + Mn(s) --> 2 MnO(s) DH = -59.5 kcal
    Find Hf of MnO2 (the heat of formation of MnO2 from its elements).
  8. Find DH for the following reaction using the information given below.
    2 Na2O2(s) + 4 HCl(g) --> 4 NaCl(s) + 2 H2O(1) + O2(g)

    2 Na2O2(s) + 2 H2O(l) --> 4 NaOH(s) + O2(g) DH = -30.2 kcal
    NaOH(s) + HCl(g) --> NaCl(s) + H2O(l) DH = -42.8 kcal

  9. How much heat, in kJ, is needed to boil away 100.0 g grain alcohol (ethanol) at 25.0°C.
  10. A 1.50 g piece of gold absorbed 0.162 cal when its temperature was raised by 3.50 °C. Calculate the specific heat of gold in cal/(g °C) and J/(g °C). 

Answers:  12)  6,400 J  13) 1700 cal, 7100 J  14) 170 kJ  15)  53.3 kJ  16)  3880 kJ  
17)  a) -113.04 kJ 17b)  -26.9 kJ  18)  -124.5 kcal  19)  -201.4 kcal  20)  107 kJ  
21)  0.0309 cal/(g °C), 0.129 J/(g °C)

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