1) Explain the action of the molecules at the surface of an ice cube sitting in a classroom. (Describe what the molecules are doing and use references to phase and equilibrium.)


2) Describe what is happening in a reaction that has reached equilibrium. (Discuss rate.)


3) Write the equilibrium expression for the following reactions:

  1. 2 H2 + O2 -> 2 H2O
  2. 2 SO3 > 2 SO2 + O2
  3. 2 NO -> N2 + O2
  4. N2 + 3 H2 -> 2 NH3

4) For each of the following reactions, state whether the reaction will shift to the right (make more product) or shift to the left (make more reactant) when the following changes are made.

2 H2 + O2 -> 2 H2O

a. Adding O2

b. Adding H2O

c. Increasing the pressure

2 SO3 -> 2 SO2 + O2

a. Increasing the pressure

b. Adding SO2

c. Removing SO3


N2 + 3 H2 -> 2 NH3 + 92 kJ

a. Decreasing the pressure

b. Adding NH3

c. Removing NH3

d. Increasing the temperature

e. Decreasing the temperature


5) In each of the examples above, why do the reactions shift? (Hint: use the term rate.)

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