Unit 11 Quiz--Equilibrium Constants

Multiple Choice (Choose the best answer.)

  1. An equilibrium constant for a reaction varies with

    concentration of reactants.

    concentration of products.

    presence of a catalyst.

    temperature.

    All of the above.


  2. The equilibrium constant ( Keq ) for the reaction, 2 SO2 (g) + O2 (g) 2 SO3 (g), is:

    { 2 [SO2] + [O2] } / 2 [SO3]

    { [SO2] 2 x [O2] } / [SO3] 2

    2 [SO3] / { 2 [SO2] + [O2] }

    [SO3] 2 / { [SO2] 2 x [O2] }

    None of the above.


  3. What would be the value of the equilibrium constant for the expression, 2 A B + C, if [A], [B], and [C] are 2.0 M, 3.0 M, and 4.0 M respectively.

    0.33

    3.0

    3.5

    6.0

    None of the above are correct.



  4. The reaction, X Y has a Keq = 3. If the reaction reaction starts out with 12 Xs, how many Xs and Ys will there be when equilibrium is reached? (See the picture at right.)

    12 X and 0 Y

    9 X and 3 Y

    3 X and 9 Y

    12 X and 36 Y

    None of these.


  5. Calcium hydroxide, Ca(OH)2, is only slightly soluble in water. The Ksp expression for Ca(OH)2 is:

    Ksp= [Ca][OH]2

    Ksp = [Ca][2 x OH]

    Ksp = [Ca 2+][2 x OH -]

    Ksp = [Ca 2+][OH -]

    Ksp = [Ca 2+][OH -] 2


  6. The Ksp of CaCO3 is 4.5 x 10 -9. What is the molar solubility of CaCO3?

    6.7 x 10 -5 M

    2.3 x 10 -9 M

    4.5 x 10 -9 M

    2.0 x 10 -15 M

    None of these are correct.


  7. The solubility of CaF2 is 2.1 x 10 -4. Find the Ksp of CaF2.

    4.4 x 10-8

    9.3 x 10 -12

    3.7 x 10 -11

    0.037

    None of these are correct.


  8. Reactions tend to form the most products when

    the disorder increases and the energy content increases.

    the disorder increases and the energy content decreases.

    the disorder decreases and the energy content increases.

    the disorder decreases and the energy content decreases.

    None of the above are correct.


  9. Which of the reactions below would you expect to largest equilibrium constant in terms of disorder and energy?

    MgCO3 (s) MgO (s) + CO2 (g); H = 13.9 KJ

    2 PbS (s) + 3 O2 (g) 2 SO2 (g) + 2 PbO (s); H = - 835.0 KJ

    C2H5OH (l) C2H5OH (g); H = 43 KJ

    C2H4 (g) + H2 (g) C2H6 (g); H = -137 KJ

    4 HCN (l) + 5 O2 (g) 4 CO2 (g) + 2 H2O (g) + 2 N2 (g); H = - 2500 KJ


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