Answer: 2.5 moles
2H2 + O2 = 2H2O
This implies that 2 moles of oxygen is needed to react with one mole of oxygen to form 2 moles of water
It also implies that
2 moles of hydrogen requires 32 grams of oxygen
? moles of hydrogen would require 40 g of oxygen
2 x 40/32 = 2.5 moles
