How do you calculate the volume of 30.0% (w/w) H2O2 needed to prepare 25.0 mL of a 3.6 M hydrogen peroxide solution?

Answer 1

Start with 3.6 M H₂O₂ and find the mass of H₂O₂ needed.

3.6 M = 3.6 moles/L and 25.0 ml = 0.0250 L

3.6 moles/L x 0.025 L = 0.090 moles. Since the molar mass of H₂O₂ is 34 g/mole, we have....

0.090 moles H₂O₂ x 34 g/mole = 3.06 g H₂O₂ required.

Now, we can find the volume of 30% (w/w) needed to provide this mass of H₂O₂....

30% (w/w) = 30 g/100 ml = 0.30 g/ml

(x ml)(0.30 g/ml) = 3.06 g

x = 10.2 mls of 30.0% H₂O₂ needed to prepare 25.0 ml of 3.6 M H₂O₂