Question

How many moles of oxygen (O2) are required to completely react with 27.4 mol of H2?

Answer 1

2 H₂ + O₂=  2 H₂O 

2 moles H₂ ------- 1 mole O₂
27.4 moles H₂ ---- ?

27.4 * 1 / 2 = 

=  27.4 / 2

= 13.7 moles of O₂

hope this helps!