Question

Household hydrogen peroxide is an aqueous solution containing 3.0% hydrogen peroxide by mass. What is the molarity of this solution? (Assume a density of 1.01g/ml .)

Answer 1

A 3.0% by mass solution of H2O2 contains 3.0 g of H2O2 per 100 g of solution.

(3.0 g H2O2 / 100 g solution) x (1.01 g solution / 1 mL solution) x (1000 mL / L) = 30.3 g H2O2 / L

(30.3 g H2O2 / L) x (1 mole H2O2 / 34.01 g H2O2) = 0.8909 moles H2O2 / L = 0.89 M to 2 sig figs

Answer 2

Household hydrogen peroxide is an aqueous solution containing 3.0% hydrogen peroxide by mass