Target: 10 Questions in 10 minutes

An IB Chemistry data booklet is helpful

Questions 1-4 are about the hydrolysis of a compound M to form N and P. It undergoes a two-step mechanism:


Step 1:    M + H+  → MH+                 
Step 2:    MH+ + H2O  → N + P + H+


The energy profile diagram for the reaction is shown below:

Energy graph profile during reaction
1. Which of the following is true about this reaction?
  • A.   H+ is an intermediate in this reaction.
  • B.   H2O is a catalyst in this reaction.
  • C.   MH+ is an intermediate in this reaction.
  • D.   M is the only reactant in this reaction.
2. On the energy profile, which point represents a transition state of the rate-determining step of the reaction?
  • A.   Point a
  • B.   Point b
  • C.   Point c
  • D.   Point d
3. Which of the following is the rate equation for this reaction?
  • A.   Rate = k[M]
  • B.   Rate = k[MH+]
  • C.   Rate = k[M][H+]
  • D.   Rate = k[MH+][H2O]
4. Which of the following statements is NOT correct about this reaction?
  • A.   The overall reaction is exothermic.
  • B.   The overall equation of the reaction is M + H2O  → N + P
  • C.   When the concentration of M increases, the rate of the reaction increases.
  • D.   Step 1 of the reaction has a molecularity of 1
5. How does the rate constant of a reaction vary when temperature changes?
  • A.   The rate constant is independent of the temperature.
  • B.   The rate constant is directly proportional to the temperature.
  • C.   The rate constant is inversely proportional to the temperature.
  • D.   The rate constant increases exponentially with $ -1\over \text{temperature} $

6. For a reaction Q + R  → S + T, the rate constant k was measured for the reaction at two different temperatures and the results are shown below:

T / Kelvin k / s-1
300 0.005
350 0.009

What is the activation energy, in kJ mol-1, for this reaction? 		 
  • A.   1.2
  • B.   10
  • C.   240
  • D.   85000

7. Which of the following affects the value of the Arrhenius factor in a reaction?

I. The orientation of the reactant particles.
II. The collision frequency between the reactant particles.
III. The activation energy of the reaction
  • A.   I and II only
  • B.   I and III only
  • C.   II and III only
  • D.  II only

8. What is the activation energy (in kJ mol-1) of a reaction with the following Arrhenius plot?

Arrhenius plot for calculation
  • A.   0.078
  • B.   9.4
  • C.   78
  • D.   130

Questions 9-10 are about a reaction with the following energy profile:

Energy profile #2 during reaction

  
9. Which line represents the activation energy of the rate-determining step of this reaction?
  • A.   Line 1
  • B.   Line 2
  • C.   Line 3
  • D.   Line 4
10. What is the order of the reaction with respect to V?
  • A.   3
  • B.   2
  • C.   1
  • D.   0