Water is 11% hydrogen and 89% oxygen by mass. How many grams of oxygen are in a 250 g glass of water?

mass O2 = 222.5 g

Explanation:

%wt = ((mass compound) / (mass sln)) * 100

balance reaction:

2H2 + O2 ↔ 2H2O

∴ %wt H2 = 11 % = ((mass H2) / (mass H2O)) * 100

∴ %wt O2 = 89 % = ((mass O2) / (mass H2O)) * 100

∴ mass H2O 250 g

⇒ mass O2 = (0.89) (250 g)

⇒ mass O2 = 222.5 g