kinetics                         test     [70 points]                   honors 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]

 

kinetics_2

kinetics_4

kinetics_6

Rate kinetics_8

 

 

 

kinetics_10

 

 

 

 

 

 

 

kinetics_10_0

 

  

2.  Describe / rationalize the use of graphical analysis to determine the activation energy of a reaction.  [10 points]

 

3. Based on the following hypothetical experimental data

 

expt

[N2] (M)

[H2] (M)

kinetics_12

1

1.0

1.0

1.0

2

2.0

1.0

4.0

3

4.0

2.0

32.0

 

for the reaction:  N2  +  H2  à   NH3, determine the rate law, including the value and units of the rate constant.  [15 points]

   

 

4. 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

 


5. 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

 

 

6. 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]

 

 

 

7.  What is a catalyst ?  [2 points]