During a chemical reaction, substances combine with each other in definite proportions by mass. In the following two equations, the same two reactants, hydrogen and oxygen, combine but in different mass ratios, therefore forming two different products. For the two balanced reactions below, determine the mass ratio of the two elements that make up the product formed (atomic mass x number of element in substance, excluding coefficient).
2H₂ + O₂ → 2H₂O
H₂ + O₂ → H₂O₂
Mass of oxygen in grams: ___