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Chemistry LibreTexts

Kinetics (Worksheet)

Name: ______________________________

Section: _____________________________

Student ID#:__________________________

Work in groups on these problems. You should try to answer the questions without referring to your textbook. If you get stuck, try asking another group for help.

1. Write the rate expression in terms of \(\Delta\)[reactant]/\(\Delta\)t  and  \(\Delta\)[product]/\(\Delta\)t for the reaction:

\[N_2 + 3H_2 \rightarrow 2NH_3\]

2. Determine

  1. The order of each reactant,
  2. The order of the reaction,
  3. Write the rate law and
  4. Calculate the rate constant, \(k\), for the following data:

Experiment

\({[A]}\) 

\({[B]}\) 

initial rate

#1. 

\(0.20\, M\)

\(0.10\, M\)

\(3.50 \times 10^{-3} M/s\)

#2. 

\(0.4\, M\)

\(0.10\, M\)

\(7.00 \times 10^{-3} M/s\)

#3. 

\(0.40\, M\)

\(0.40\, M\)

\(7.00 \times 10^{-3} M/s\)

 

3.  The decomposition of \(A_2B_3\) is second order with a \(k = 6.5 \times 10^{-5} M^{-1}s^{-1}\) at 25oC. If the initial concentration is \(0.50\, M\), what is the concentration after \(3 min\)?

  1. What is the half-life for this reaction?

 

4. The decomposition of \(AB\) is first order with a \(k = 2.3 \times 10^{-7} s^{-1}\) at 45oC. If the initial concentration is 0.25 M, what is the concentration after 2.3 min?

  1. What is the half-life for this reaction?

 

5 What is the concentration of reactant after 2.5 minutes if the initial concentration was \(0.100\, M\) and \(k = 6.93 \times 10^{-3} s^{-1}\) for a first order reaction?

  1. What is the half-life?

 

6. For the first order reaction:

\[SO_2Cl_2 \rightarrow SO_2 + Cl_2\]

How long will it take to reach \(0.31 \times 10^{-3}\, M\) if the initial concentration was \(1.25 \times 10^{-3}\; M\) and \(k = 0.17 hr^{-1}\)?

 

7. The rate constant is \(k = 1.5 \times 10^{-2} M^{-1}s^{-1}\) for the second order reaction

  \[A \rightarrow B\]

  1. If the initial concentration of \(A\) is \(0.10\, M\), what is the concentration of \(A\) after 4 min?
  2. what is the half-life?