Determine the value and units of the rate constant
Units for the rate constant: The units of a rate constant will change depending upon the overall order.The units of rate are always M/s or Ms â1 To find the units of a rate constant for a particular rate law, simply divide the units of rate by the units of molarity in the concentration term of the rate law.. The reaction rate law expression relates the rate of a reaction to the concentrations of the reactants.Each concentration is expressed with an order (exponent).The rate constant converts the concentration expression into thecorrect units of rate (Ms â1).
Conclusion: the reaction is first order in A. 3) The rate law for this reaction is: 4) We can use any set of data to calculate the rate constant: 9.6 x 10 -6 M s -1 = k (0.040 M) (0.040 M). k = 0.0060 M -1 s -1. Comment: remember that M -1 s -1 is often written as L mol -1 s -1.ften the rate constant unit is rendered thusly: L 2 mol -2 s -1. Note that the overall order of the rate law is third order and that this is reflected in the unit associated with the rate constant.