Question

In the reaction, A -----> Products, the rate constant is 3.6 x 10^−4 s−1. If the initial concentration of A is 0.548 M, what will be the concentration of A (in M) at t = 99.2 s?
Only enter the numerical value with three significant figures in the answer . Do NOT type in the unit (M).

Answer 1

Answer:

0.529

Explanation:

Let's consider the reaction A → Products

Since the units of the rate constant are s⁻1, this is a first-order reaction with respect to A.

We can find the concentration of A at a certain time t ($[A]_{t}$) using the following expression.

$[A]_{t}=[A]_{0}.e^{-k\times t}$

where,

[A]₀: initial concentration of A

k: rate constant

$[A]_{t}=0.548M.e^{-3.6\times 10^{-4}s^{-1}\times 99.2s }$

$[A]_{t}=0.529 M$