Problem: Consider the decomposition of liquid hydrogen peroxide (H2O2) to form water and oxygen.What is the heat of formation for gaseous oxygen?

FREE Expert Solution

We’re being asked to determine the standard enthalpy change of formation (ΔH˚f) for oxygen. Recall that ΔH˚rxn can be calculated from the enthalpy of formation (ΔH˚f) of the reactants and products involved


H°rxn=H°f,products-H°f,reactants



The chemical equation for the reaction is:

H2O2(l)→ O2(g) + H2O(l)


This equation is not yet balanced. To balance it, we have to make sure that the number of elements on both sides is equal.


Balance O: We have 2 O on the reactant side and 3 O on the product side – add a coefficient of 2 to H2O:

H2O2(l)→ O2(g)2 H2O(l)

Balance H: We have 2 H on the reactant side and 4 H on the product side – add a coefficient of 2 to O2:

2 H2O2(l)→ O2(g)2 H2O(l)


97% (237 ratings)
View Complete Written Solution
Problem Details

Consider the decomposition of liquid hydrogen peroxide (H2O2) to form water and oxygen.

What is the heat of formation for gaseous oxygen?

Frequently Asked Questions

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Enthalpy of Formation concept. You can view video lessons to learn Enthalpy of Formation. Or if you need more Enthalpy of Formation practice, you can also practice Enthalpy of Formation practice problems.