A reactant R is being consumed in a first-order reaction. What fraction of the initial R is consumed in 4.0 half-lives?

Question

Quizplus · Accepted Answer

In a first-order reaction, the amount of reactant remaining after n half-lives is given by the formula (1/2)^n. After 4 half-lives, the fraction of the initial reactant remaining is (1/2)^4 = 1/16. Therefore, the fraction consumed is 1 - 1/16 = 15/16 = 0.9375, which rounds to 0.94.

A Reactant R Is Being Consumed in a First-Order Reaction