When 3.4 moles of hydrogen gas react with excess oxygen how many moles of water will be produced

1. start with balanced equation.

2 H2 (g) + O2 (g) 2 H 2O (g)

2. Use stoichiometry

(3.4moles of H) (2moles of H2O/2moles of H)

The moles of H will cancel, leaving you with moles of H2O.

The answer is 3.4 moles of H2O