The kinetic data for a chemical reaction is given in the following table: Time (min) 0 10 20 Concentration ( M ) 0.40 0.20 0.10 Based on the above data, what will be the concentration of the reactant at 40 minutes?

Step-by-step solution

From the table, the concentration of the reactant reduces to half its initial value every 10 minutes ( 0.40 M 0.20 M 0.10 M ). This constant half-life indicates a first-order reaction with t_ 1/2 = 10 min . We need to find the concentration at t = 40 min . Number of half-lives, n = t t_ 1/2 = 40 10 = 4 Concentration after 4 half-lives = [ A ]₀ 2^n = 0.40 2^4 = 0.40 16 = 0.025 M . Answer: 0.025 M