A mixture containing 10 g of H ₂ gas and 64 g of O ₂ gas is ignited to form water. If the percentage yield of the reaction is 75 % , the actual mass of water formed in grams is _________.

Step-by-step solution

The balanced chemical equation for the combustion of hydrogen is: 2 H ₂ + O ₂ 2 H ₂ O First, calculate the number of moles of each reactant: Moles of H ₂ = 10 2 = 5 moles Moles of O ₂ = 64 32 = 2 moles To identify the limiting reagent, divide the moles by the stoichiometric coefficients: For H ₂ : 5 2 = 2.5 For O ₂ : 2 1 = 2 Since 2 From the balanced equation, 1 mole of O ₂ produces 2 moles of H ₂ O . Therefore, 2 moles of O ₂ will theoretically produce 2 2 = 4 moles of H ₂ O . Theoretical mass of water = 4 18 = 72