text: The units of the rate constant depend on the overall order of reaction.
  If concentration is measured in units of mol·L (sometimes abbreviated as M), then
  * For order (m + n), the rate constant has units of mol·L·s (or M·s)
  * For order zero, the rate constant has units of mol·L·s (or M·s)
  * For order one, the rate constant has units of s
  * For order two, the rate constant has units of L·mol·s (or M·s)
  * For order three, the rate constant has units of L·mol·s (or M·s)
  * For order four, the rate constant has units of L·mol·s (or M·s)