After a certain pesticide is applied to crops, its decomposition is a first order reaction with a half life of 56 days. What is the rate constant, k, for the decomposition reaction?

Solution: The equation for the first order half life is t1/2 = 0.693/k where t1/2 is the half life and k is the rate constant. Now, lets plug in our half life

56days = 0.693/k

k=0.012 days