Chem Midterm # 1

  1. A reaction is found to have an activation energy of 108 kJ/mol. If the rate constant for this reaction is 4.60 x 10-6 s-1 at 275 K, what is the rate constant at 366 K?

    A) 0.580 s-1
  2. Which of the following statements is FALSE?

    Note if you chose “a”, that is acceptable since in the case of zero order reaction that statement is false,
    and it does not specify the reaction order.
    A) Teh half life of a first order reaction is dependent on the intial concentration of reactant.
  3. Which of the following reactions would you predict to have the smallest orientation factor?

    D) NOCl2 + NO >> 2 NOCl
  4. What is the overall order of the following reaction, given the rate law?
    2 X + 3 Y >> 2 Z Rate =k[X]1[Y]2
    a) 3rd order
    b) 5th order
    c) 2nd order
    d) 1st order
    e) 0th order
    a) 3rd order
  5. Consider the following reaction, equilibrium concentrations, and equilibrium constant at a particular
    temperature. Determine the equilibrium
    concentration of H2O(g).
    C2H4(g) + H2O(g) ↔ C2H5OH(g) Kc = 9.0 x 103
    [C2H4]eq = 0.015 M [C2H5OH]eq = 1.69 M

    C) 0.013 M
  6. What are the units of k in the following rate law?
    Rate = k[X]2[Y]

    • D) 1 M2s
  7. The first-order decomposition of cyclopropane has a rate constant of 6.7 x 10-4 s-1. If the initial
    concentration of cyclopropane is 1.33 M, what is the concentration of cyclopropane after 644 s?

    C) 0.86
  8. The first-order rearrangement of CH3NC is measured to have a rate constant of 3.61 x 10-15 s-1 at 298 K and a rate constant of 8.66 x 10-7 s-1 at 425 K. Determine the activation energy for this reaction.

    E) 160. kJ/mol
  9. Write a balanced chemical equation that corresponds to the following equilibrium constant expression.
    K = [F-][H3O+]

    C) HF(aq) + H2O(l) ↔ F-(aq) + H3O+(aq)
  10. Given the following rate law, how does the rate of reaction change if the concentration of Y is doubled?
    Rate = k[X][Y]2

    D) The rate of the reaction will increase by a factor of 4.
Card Set
Chem Midterm # 1
Midterm #1