Question

An aqueous solution of H2O2 has a concentration of 9.79M. Calculate the percent by mass of H2O2 in the solution. (density of the H2O2 solution is 1.11g/mL)

Answer 1

percent by mass H₂O₂ = 30.0 %

Explanation

Let us take 1 L of solution

Volume of solution = 1 L = 1000 mL

concentration H₂O₂ = 9.79 M

moles H₂O₂ = (concentration H₂O₂) * (volume of solution in Liter)

moles H₂O₂ = (9.79 M) * (1 L)

moles H₂O₂ = 9.79 mol

mass H₂O₂ = (moles H₂O₂) * (molar mass H₂O₂)

mass H₂O₂ = (9.79 mol) * (34.0 g/mol)

mass H₂O₂ = 332.86 g

mass of solution = (volume of solution) * (density of solution)

mass of solution = (1000 mL) * (1.11 g/mL)

mass of solution = 1110 g

percent by mass H₂O₂ = (mass H₂O₂ / mass of solution) * 100

percent by mass H₂O₂ = (332.86 g / 1110 g) * 100

percent by mass H₂O₂ = (0.300) * 100

percent by mass H₂O₂ = 30.0 %