kinetics                         test     [60 points]                   Chem

 

For problems involving calculations, show your work in an organized manner, include any relevant equation (or formula and conversion factor(s)), put the proper units in your calculations / answer, and have the proper number of significant figures in your answer.              

 

Academic Honesty:   The answers on this test are my own and I am using only the allowed set of notes as described in the syllabus.  I have not discussed the test questions with anyone before or during the test nor have I seen the test questions prior to the exam.  If you violate any of the preceding items or do not sign, your semester grade is a F.

 

                                                                                                Signature:  ___________________

 

  1.  In regards to the reaction:  N2  +  H2  à  NH3, fill-in the below table; justify your answer.  [18 points]

 

image 2

image 4

image 6

Rate image 8

 

 

 

image 10

 

 

 

 

 

 

image 10_0

 

 

 2.  Based on the following hypothetical experimental data, determine the value of the exponents and the value / units of the rate constant in the rate law for the reaction of HCl  +  Na2S2O3  à  products.  [15 points]

 

Expt

[HCl]  (mM)

[Na2S2O3]  (mM)

Rate (mM / minute)

1

1.0

1.0

5.0

2

2.0

1.0

10.0

3

1.0

2.0

20.0

 

 

 3. Based on the following hypothetical experimental data, determine the value of the exponents in the rate law for the reaction of HCl  +  Na2S2O3  à  products.  [10 points]

 

Expt

[HCl]  (mM)

[Na2S2O3]  (1.0 mM)

time (seconds)

1

0.05

0.05

60.0

2

0.1

0.05

30.0

3

0.05

0.1

15.0

 

 

4. Sketch the reaction energy profile for an  ___ reaction.  label the axis, activation energy for the forward reaction, activation energy for the backward reaction, and the change in enthalpy in the reaction.  [10 points]

 

   a.  Endothermic

 

   b.  Exothermic

 

 

5. If a hypothetical reaction consumes 75 kJ of heat and the activation energy of the forward reaction is 100 kJ, what is the activation energy of the backward reaction ?  [5 points]

 

 

 

6.  What is a catalyst ?  [2 points]