Compounds decomposing

Question

For the reaction where H₂O₂ (aq) decomposes into liquid water and oxygen gas. How many grams of oxygen gas will be produced from 750.0 L of 100 mM H₂O₂?

Answer 1

Write the balanced equation:

2H₂O₂(aq) ==> 2H₂O(l) + O₂(g) .. balanced equation

Find the moles of H2O2 present:

100 mM H₂O₂ means 100 millimoles per liter

There are 750.0 liters. So 100 mmoles / L x 750.0 L = 75,000 millimoles H₂O₂

Converting this to moles, we have ... 75,000 mmoles x 1 mol / 1000 mmoles = 75.00 moles H₂O₂

Use dimensional analysis, the stoichiometry of the balanced equation and molar mass of O₂ to get answer:

75.0 mols H₂O₂ x 1 mol O₂ / 2 mol H₂O₂ x 32 g O₂ / mol O₂ = 1200 g O₂ = 1.23x10³ g O₂