Problem: Hydrogen peroxide decomposes into water and oxygen by the following reaction:2 H2O2(aq) ↔ 2 H2O(l) + O2(g) ΔHrxn = -94.64 kJ/molExperimental evidence tells us that this reaction is first order with respect to hydrogen peroxide, with an activation energy of 75.3 kJ/mol at 300 K.a)What is the activation energy for the reverse reaction?b)Sketch the reaction pathway below. Be sure to label the axes, reactants, products, transition state, and energies.c)Assuming the forward and reverse reaction have the same frequency factor, what is the equilibrium constant for this reaction? (when you answer this question, you will need to write down the value for K, and the temperature that you calculated K at.)d)Catalase is an enzyme found in nearly all living organisms that catalyzes the hydrogen peroxide decomposition reaction shown above by lowering the activation energy of the forward reaction to 8.8 kJ/mol. How many times faster does hydrogen peroxide decompose in the presence of catalase?e)What temperature would we need to decompose hydrogen peroxode at to achieve the same rate increase achieved with catalase?

FREE Expert Solution

a) To determine the activation energy for the reverse reaction:


Ea,rev=Ea,fwd+Hrxn,rev


ΔHrxn,rev = -ΔHrxn, fwd = -(-94.64 kJ/mol) 

ΔHrxn,rev = 94.64 kJ/mol

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Problem Details

Hydrogen peroxide decomposes into water and oxygen by the following reaction:

2 H2O2(aq) ↔ 2 H2O(l) + O2(g) ΔHrxn = -94.64 kJ/mol

Experimental evidence tells us that this reaction is first order with respect to hydrogen peroxide, with an activation energy of 75.3 kJ/mol at 300 K.

a)What is the activation energy for the reverse reaction?

b)Sketch the reaction pathway below. Be sure to label the axes, reactants, products, transition state, and energies.

c)Assuming the forward and reverse reaction have the same frequency factor, what is the equilibrium constant for this reaction? (when you answer this question, you will need to write down the value for K, and the temperature that you calculated K at.)

d)Catalase is an enzyme found in nearly all living organisms that catalyzes the hydrogen peroxide decomposition reaction shown above by lowering the activation energy of the forward reaction to 8.8 kJ/mol. How many times faster does hydrogen peroxide decompose in the presence of catalase?

e)What temperature would we need to decompose hydrogen peroxode at to achieve the same rate increase achieved with catalase?

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