Question

The decomposition of hydrogen peroxide to form water and oxygen gas releases 196.6 kJ per mole of hydrogen peroxide. This reaction occurs when hydrogen peroxide is placed on a skin cut to sterilize it. How much heat is released when 5.25 moles of H2O2 decompose?

Answer 1

Answer: The amount of heat released for 5.25 moles of hydrogen peroxide decomposed is 1032.15 kJ

Explanation:

We are given:

Heat released in the reaction = 196.6 kJ per mole of hydrogen peroxide

Heat released for 2 moles of hydrogen peroxide decomposed = $(2\times 196.6)=393.2kJ$

Sign convention of heat:

When heat is absorbed, the sign of heat is taken to be positive and when heat is released, the sign of heat is taken to be negative.

The chemical equation for the decomposition of hydrogen peroxide follows:

$2H_2O_2\rightarrow 2H_2O+O_2;\Delta H=-393.2kJ$

We are given:

Moles of hydrogen peroxide decomposed = 5.25 moles

By Stoichiometry of the reaction:

2 moles of hydrogen peroxide decomposed, the amount of heat released is 393.2 kJ

So, when 5.25 moles of hydrogen peroxide decomposed, the amount of heat released will be = $\frac{393.2}{2}\times 5.25=1032.15kJ$

Hence, the amount of heat released for 5.25 moles of hydrogen peroxide decomposed is 1032.15 kJ