How many moles of h2o are produced when using 7 moles of h2

1) Write the balaced chemical equation:

H2 + 2O2 → 2H2O

2) Infere the molar ratios:

1 mol H2 : 2 mol of water

3) Make the calculus as the direct proportion relation:

[2 mol H2O] / [1 mol H2] * 7 mol H2 = 14 mol H2

As you see you produce the double number of moles of H2O than number of moles of H2 used.

Answer: 14 moles