The initial concentration of reactant in a first-order reaction is 0.27 M. The rate constant for the reaction is 0.75 s^-1. What is the concentration (mol/L)of reactant after 1.8 s?

Question

Quizplus · Accepted Answer

We can use the first-order rate law equation:

ln([A]t/[A]0) = -kt

where [A]0 is the initial concentration, [A]t is the concentration at time t, k is the rate constant, and ln is the natural logarithm.

Solving for [A]t, we get:

[A]t = [A]0 * e^(-kt)

Plugging in the given values, we get:

[A]t = 0.27 * e^(-0.75*1.8) = 0.070 M

Therefore, the concentration of reactant after 1.8 s is 0.070 mol/L, which is answer choice C.

The Initial Concentration of Reactant in a First-Order Reaction Is