Sodium peroxide + water

Sodium peroxide + water → Sodium Hydroxide + Hydrogen Peroxide
Na₂O₂ + 2H₂O → 2NaOH + H₂O₂

Na₂O₂ is 78 g/mol
H₂O is 18 g/mol
NaOH is 40
H₂O₂ is 34

1 mol of Na₂O₂ + 2 mol of H₂O → 2 mol of NaOH + 1 mol of H₂O₂
78 g of Na₂O₂ + 36 g of H₂O → 80 g of NaOH + 34 g of H₂O₂