Question

Given the following set of data from the decomposition of hydrogen peroxide,

how is the initial rate of the reaction (between time 0 and 300 seconds)
different from the rate of the reaction between 1800 and 3000 seconds?
[H202 M
Time (s)
2.0
0
1.6
300
1.4
600
1.1
1200
0.72
1800
0.15
3000

Answer 1

The initial rate of reaction is higher than the rate at later stages, calculated by dividing the change in concentration by the time interval for each respective period.

Step-by-step explanation:

To determine how the initial rate of reaction of hydrogen peroxide decomposition differs between time 0 and 300 seconds and time 1800 to 3000 seconds, we must calculate the rate at which the concentration of H2O2 changes during these intervals. For the initial rate, between 0 and 300 seconds, the concentration decreases from 2.0 M to 1.6 M. The rate can be found by dividing the change in concentration (2.0 M - 1.6 M = 0.4 M) by the time interval (300 s).

For the latter rate, between 1800 and 3000 seconds, the concentration decreases from 0.72 M to 0.15 M. Similarly, the rate is the change in concentration (0.72 M - 0.15 M = 0.57 M) divided by the time interval (3000 s - 1800 s = 1200 s).

Comparing these two rates will show that the initial rate is generally higher than the rate towards the end of the reaction, consistent with the characteristics of first-order reactions, where the rate decreases as the concentration of the reactant decreases.