Practice Exercises

Record your answers on a separate sheet of paper.

1. For the reaction A + B ⇌ C + D, the equilibrium constant can be expressed as:

   1. 
      
      
   2. 
      
      
   3. 
      
      
   4. 

2. The concentrations in an expression of the equilibrium constant are given in

   1. mol/mL
   2. g/L
   3. gram-equivalents/L
   4. mol/L

3. In the equilibrium expression for the reaction

   

   K_sp is equal to

   1. 
      
      
   2. 
      
      
   3. 
      
      
   4. 

4. The K_w of water at 298 K is equal to

   1. 1 × 10⁻⁷
   2. 1 × 10⁻¹⁷
   3. 1 × 10⁻¹⁴
   4. 1 × 10⁻¹

5. The pH of a solution that has a hydrogen ion concentration of 1 × 10⁻⁴ mole/liter is

   1. 4
   2. −4
   3. 10
   4. −10

6. The pH of a solution that has a hydroxide ion concentration of 1 × 10⁻⁴ mole/liter is

   1. 4
   2. −4
   3. 10
   4. −10

7. A small value for K_a, the acid equilibrium constant, indicates that

   1. the concentration of the un-ionized molecules must be relatively small compared with the ion concentrations
   2. the concentration of the ionized molecules must be larger than the ion concentrations
   3. the substance ionizes to a large degree
   4. the concentration of the un-ionized molecules must be relatively large compared with the ion concentrations

8. In the Haber process for making ammonia, an increase in pressure favors

   1. the forward reaction
   2. the reverse reaction
   3. neither reaction

9. A change in which of these conditions will change the K of an equilibrium given as a starting point?

   1. Temperature
   2. Pressure
   3. Concentration of reactants
   4. Concentration of products

10. If Ca(OH)₂ is dissolved in a solution of NaOH, its solubility, compared with that in pure water, is

    1. increased
    2. decreased
    3. unaffected

11. The following questions are in the format that is used on the SAT Subject Area Test in Chemistry. If you are not familiar with these types of questions, study pages xiii–xiv before doing the remainder of the review questions.

12. Directions: The following set of lettered choices refers to the numbered questions immediately below it. For each numbered item, choose the one lettered choice that fits it best. Every choice in the set may be used once, more than once, or not at all.

13. 1. Questions 11–15

       Complete the sentence with the appropriate choice.

       1. the free energy is always negative
       2. the free energy is negative at lower temperatures
       3. the free energy is negative at high temperatures
       4. the free energy is never negative
       5. the system is at equilibrium, and there is no net reaction

    11. When enthalpy is negative and entropy is positive,

    12. When enthalpy is positive and entropy is positive,

    13. When enthalpy is negative and entropy is negative,

    14. When enthalpy is positive and entropy is negative,

    15. When ΔG, free energy, is zero,