The decomposition of hydrogen peroxide in dilute sodium hydroxide at 20 °C is first order in H2O2. H2O2 (aq) H2O (l) + ½ O2 (g) During one experiment it was found that the H2O2 concentration dropped from 5.1610-2 M at the beginning of the experiment to 1.9510-2 M in 832 min. What is the value of the rate constant for the reaction at this temperature? min-1

Question

Chemistry

Sherlyn

4 February, 01:57

The decomposition of hydrogen peroxide in dilute sodium hydroxide at 20 °C is first order in H2O2. H2O2 (aq) H2O (l) + ½ O2 (g) During one experiment it was found that the H2O2 concentration dropped from 5.1610-2 M at the beginning of the experiment to 1.9510-2 M in 832 min. What is the value of the rate constant for the reaction at this temperature? min-1

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Cedric Buckley · Answer 1

The rate constant is 1.98*10^-3 min^-1

Explanation:

The reaction follows a first order

Rate = k[H2O2] = change in concentration of H2O2/time

Initial concentration of H2O2 = 5.16*10^-2 M

Concentration of H2O2 in 832 min = 1.95*10^-2 M

Change in concentration = 5.16*10^-2 - 1.95*10^-2 = 3.21*10^-2 M

Time = 832 min

1.95*10^-2k = 3.21*10^-2/832

k = 3.86*10^-5/1.95*10^-2 = 1.98*10^-3 min^-1