For a zero-order reaction, the rate of the reaction is independent of the concentration of the reactant(s). The integrated rate law for a zero-order reaction can be expressed as:

[A]_t = [A]₀ – kt

where:

• [A]_t is the concentration of the reactant A at time t
• [A]₀ is the initial concentration of reactant A
• k is the rate constant of the reaction
• t is the reaction time

In this integrated rate law, the concentration of reactant A at any given time t is equal to the initial concentration [A]₀ minus the product of the rate constant k and the reaction time t.

The unit of the rate constant (k) for a zero-order reaction is usually expressed as concentration/time (e.g., M/s).