how many moles of oxygen are needed to produce 15.4 moles of water?

Answer 1

2H₂+O₂→ 2H₂O

according to coefficients of balanced equation:

1 mol O2 = 2 mol H2O

so,

? mol O2 = 15.4 mol H2O

15.4 mol H2O (1 mol O2 / 2 mol H2O)=7.7 mol O2