If the reaction 3A + B + C 2D + E is first order overall, which of these could be the units of its rate constant, k?

Question

If the reaction 3A + B +  C  2D + E is first order overall, which of these could be the units of its rate constant, k?

Quizplus · Accepted Answer

The rate constant for a first order reaction has units of 1/s. This is because the rate of the reaction is directly proportional to the concentration of the reactant, and the units of concentration are usually in moles per liter (M). Therefore, the rate of the reaction can be expressed as k[A] where k is the rate constant and [A] is the concentration of the reactant. The units of k must cancel out the units of concentration ([A]), which are usually expressed in M, so the units of k must be 1/s.

If the Reaction 3A + B + C