What are the units of k in a second order reaction?

Given the following rate law, how does the rate of reaction change if the concentration of Y is doubled?

            Rate = k [X][Y]²

What data should be plotted to show that experimental concentration data fits a second-order reaction?  

How many half-lives are required for the concentration of reactant to decrease to 1.56% of its original value?

The rate constant for a second-order reaction is 0.54 M^-1s^-1.  What is the half-life of this reaction (in seconds) if the initial concentration is 0.27 M?

The first-order decomposition of cyclopropane has a rate constant of 6.7 x 10-4 s-1.  If the initial concentration of cyclopropane is 1.33 M, what is the concentration (in M) of cyclopropane after 644 s?

For a reaction, what generally happens if the temperature is increased?

The first-order rearrangement of CH₃NC is measured to have a rate constant of 3.61 x 10^-15 s^-1 at 298 K and a rate constant of 8.66 × 10^-7 s^-1 at 425 K.  Determine the activation energy (in kJ/mol) for this reaction.