Chapter 14

Q. 14.2.1

For the decomposition of hydrogen peroxide in dilute sodium hydroxide at 20 °C,
2 H_{2}O_{2}(aq) → 2 H_{2}O(ℓ) + O_{2}(g)
the following data have been obtained:

What is the average rate of disappearance of H_{2}O_{2} over the period from 0 min to 434 min?

t (min) [H_{2}O_{2}] (mol/L)
0 0.0912
434 0.0566
868 0.0351
13.2 0.0218


Verified Solution

You are asked to determine the average rate of disappearance of a reactant over a given period of time.
You are given the balanced chemical equation and data showing the reactant concentration as a function of time.
Average reaction rate is equal to the change in concentration over the change in time.

rate = -\frac{\Delta \left[H_{2}O_{2}\right] }{\Delta t}=-\frac{\left(0.0566\text{ M}-0.0912 \text{ M}\right) }{\left(434\text{ min}-0\text{ min}\right) } =7.97\times 10^{-5} M/min