Chemistry 2710 Spring 2000 Quiz 3 solution

1. If the reaction obeys a first-order rate law, a plot of vs t should be linear.

   

   As can be seen from the following graph, the data fit a line very well:

   

   This confirms the rate law.

2. The rate constant is the negative of the slope, obtained by regression: .
3. 15min is 900s. The integrated rate equation is

   

   where x represents the concentration of indium (I) ions. Accordingly,

   

   If this much remains at 900s, then has reacted. Since the volume is 0.4L, the number of moles of indium (I) ions which have reacted is 1.96mmol. By stoichiometry, the number of moles of indium metal formed is therefore . The mass of indium metal formed is therefore or 0.15g.