How many moles of water are consumed if 0.729 mol H3PO4 are produced?

1) State the equation that represents the chemical reaction

P2O5 + 3H2O → 2H3PO4

2) State the molar ratios: 1 mol P2O5 : 3 mol H2O : 2 mol H3PO4

3) Use the proportions 3molH2O / 2 mol H3PO4

0.729 mol H3PO4 * [ 3 mol H2O / 2 mol H3PO4] = 1.094 mol H2O

Answer: 1.094 mol of water