Chemistry 2710 Review Problems: Hints and Answers

1. 2. 

   3. See course notes.
   4. 

2. 

   If the pressure of X is small, the process might become more significant than activation by the inert gas so that this step would have to be added to the mechanism.

3. 1. 
   3. The answer depends (by a factor of 2) on how you wrote your overall reaction. If you wrote it as I did, the rate is

      

   4. Most of the time, the SSA gives a rate law of similar simplicity to the EA, but not in this case. The SSA value of x satisfies the quadratic equation

      

      Taking the positive root and computing the reaction velocity as above, we find

      

5. 1. The bromide ions function as a catalyst.
   2. Hints: We need to use an equation for conservation of bromine ions, by analogy to our treatment of enzyme conservation. We generally need to use a conservation law when dealing with catalysts. We also need to write down the overall reaction to know what we mean by the rate.

      The overall reaction is . The rate is therefore

      

      where we interpret as since oxygen is a gas which escapes from solution. Give or take this minor point, we get

      

      where is the total concentration of bromide in solution.

7. From an Eadie-Hofstee plot, we can calculate and . However, the fit to the data is very poor, suggesting that the simple Michaelis-Menten mechanism may not be the correct model in this case.
8. We find and . This gives . This means that must be at least .