Chapter 18 Review

1
Chapter 18 ReviewReaction Rates and Equilibrium
2
Possible Essays

• List the four factors that affect reaction rate
  and describe the effects that they have.
• What are the three stresses that can change the
  equilibrium of a reaction and explain how the
  stress would be relieved.
• What are the two factors that determine the
  spontaneity of a reaction and describe the
  favorable outcomes. Make sure to include how
  Gibbs Free Energy comes into play.
• What is the difference between a spontaneous and
  nonspontaneous reaction? Why can a spontaneous
  reaction appear to be nonspontaneous?

3
Chapter 18 Review

• Energy that is available to do work is called
  ____.
• What is the name of the minimum energy that
  colliding particles must have in order to react?

4
Chapter 18 Review

• A substance that interferes with a catalyst is
  a(n) ____.
• What is the arrangement of atoms at the peak of
  an energy barrier?
• At equilibrium, what is the rate of production of
  reactants compared with the rate of production of
  products?

5
Chapter 18 Review

• What is the equilibrium constant expression for
  the following reaction C(s) O2(g) ? CO2(g)
• Which of the following is true about the
  combustion of carbon a) the reaction is
  spontaneous, or b) entropy decreases?
• The rate of a chemical reaction normally ____ as
  reactant concentration increases.

6
Chapter 18 Review

• Why does a higher concentration make a reaction
  faster?
• The amount of disorder in a system is measured by
  its ____.
• What units represent a reaction rate?
• For a complex reaction, the reaction progress
  curve has several ____.

7
Chapter 18 Review

• What happens to a reaction at equilibrium when
  more reactant is added to the system?
• Which reaction results in the greatest increase
  in entropy a) A ?
  B, or b) A ? 2B
• If a reaction has an equilibrium constant (Keq)
  just greater than 1, how do we interpret that
  information?

8
Chapter 18 Review

• A catalyst works by ____.
• If sulfur dioxide and oxygen can be made into
  sulfur trioxide, what is the reverse reaction?
• Which variable is NOT required to calculate the
  Gibbs free-energy change for a chemical reaction
  a) change in enthalpy, or b)
  temperature in oC?

9
Chapter 18 Review

• What is the effect of adding more water to the
  following equilibrium reaction CO2 H2O ?
  H2CO3
• In an endothermic reaction at equilibrium, what
  is the effect of raising the temperature?
• The energy that is available to do work in a
  reaction is called ____.

10
Chapter 18 Review

• What is the numerical value ( or -) of Gibbs
  free-energy change for a spontaneous reaction?
• At what stage of a reaction do atoms have the
  highest energy?
• Which of the following systems has the highest
  entropy a) 10 mL of
  water at 50 oC, or b) 10 mL of water at
  100 oC?

11
Chapter 18 Review

• What happens to a catalyst in a reaction?
• An elementary reaction converts reactants to
  products in ____.
• Activation energy is ____.

12
Chapter 18 Review

• Consider the reaction
  N2(g) 3H2(g) ? 2NH3(g) What is the
  effect of decreasing the volume on the contained
  gases?
• Spontaneous reactions always ____ free energy.
• Why does a higher temperature cause a reaction to
  go faster?

13
Chapter 18 Review

• What 2 factors determine whether or not a
  reaction is spontaneous?
• What physical state of nitrogen has the highest
  entropy?
• What is another name for the catalysts in your
  body?

14
Chapter 18 Review

• What is the order of the following reaction A
  2B ? C D
• Why does a catalyst cause a reaction to proceed
  faster?
• In an equilibrium reaction with a Keq of 1 x
  108, the ____ are favored.
• Which of the following explains why melting of
  ice is spontaneous at room temperature and
  pressure a) it is accompanied
  by an increase in entropy, or b) it is
  accompanied by an increase in energy?

15
Chapter 18 Review

• The Keq of a reaction is 4 x 10-7. At
  equilibrium, the ____ are favored.
• Another name for the activated complex is ____.
• Which change would shift the following reaction
  to the right 4HCl(g) O2(g) ? 2Cl2(g)
  2H2O(g) a) decrease of pressure, or
  b) increase of pressure?

16
Chapter 18 Review

• In which of these systems is the entropy
  decreasing a) salt
  dissolving in water, or b) a liquid
  cooling?
• Given 2NClO(g) ? 2NO(g) Cl2(g) An
  analysis of the equilibrium mixture in a 1 L
  flask is NClO 1.6 mol NO 6.4 mol Cl2
  0.49 mol. Calculate the value of Keq.

17
Chapter 18 Review

• In a two-step reaction mechanism, how many
  elementary reactions occur?
• The Ksp of calcium hydroxide is 6.5 x 10-6.
  If 0.10 mol of sodium hydroxide is added to 1 L
  of 0.0010 M Ca(OH)2, what is the final
  concentration of the calcium ion?

18
Chapter 18 Review

• A mixture of hydrogen and iodine are in
  equilibrium with hydrogen iodide, as shown in the
  equation H2 I2 ? 2HI Calculate the
  concentration of HI when the Keq is 1 x 105, the
  equilibrium concentration of H2 is 0.04 M, and
  the equilibrium concentration of I2 is 0.009 M.

19
Chapter 18 Review
End of Chapter 18 Review