The reaction 2A → A2 was experimentally determined to be second order with a rate constant, k, equal to 0.0265 M–1min–1. If the initial concentration of A was 2.75 M, what was the concentration of A (in M) after 180.0 min?
1 Answer
The concentration of A was 0.195 mol/L.
Explanation:
The chemical equation for your reaction is
#"2A" → "A"_2#
Whenever a question asks you, "How long to reach a certain concentration?" or something similar, you must use the appropriate integrated rate law expression.
The integrated rate law for a second-order reaction is
where
In this problem,
∴
The concentration of A was 0.195 mol/L.