Calculating Oxygen Reacted in Chemical Reaction
If you burn 50.4 g of hydrogen and produce 4.50 × 10² g of water, how much oxygen reacted?
moles H2O = 362 / 18.02 g/mol = 20
2 H2 + O2 = 2 H2O
moles H2 = 40.5 g / 2.016 g/mol = 20
the ratio between H2 and H2O is 2 : 2 so the yield is 100%
moles O2 required = 20 / 2 = 10
mass O2 = 10 mol x 32 g/mol = 320 g
What is the amount of oxygen reacted to give 4.50 × 10² g of water? The amount of O₂ reacted to give 4.50 × 10² g H₂O = 400 g Explanation:Reaction involved: 2H₂ + O₂ → 2H₂O
In this reaction, 2 moles (2 g/mol) of H₂ reacts with 1 mole (32 g/mol) of O₂ to give 2 moles of H₂O (18 g/mol).
Given: 50.4 g H₂ reacts to give 4.50 × 10² g water.
Number of moles of H₂ burned = 50.4 g ÷ 2 g/mol = 25.2 moles
Number of moles of H₂O formed = 4.50 × 10² g ÷ 18 g/mol = 25 moles
∵ 2 moles H₂O is formed from 1 mole O₂
∴ The number of moles of O₂ that reacts to give 25 moles H₂O = 25 moles ÷ 2 moles = 12.5 moles
Therefore, the amount of O₂ reacted to give 4.50 × 10² g H₂O = 12.5 mole × 32 g/mol = 400 g