Units for Rate Law

Question

What are the units for the rate constant, k, in the following rate law:

rate=k[NH4+][NO3−]

Answer 1

If rate is given in units of concentration/time, such as M/sec or M/min, etc (and recall that M = moles/L), and [ ] is given as M, then we have M/min = k [M][M].

M/min /M2 = k

k = M^-1 min^-1 or M^-1 sec^-1, etc. Note, in general terms, the units for k would be reciprocal concentration* reciprocal time.