Yes, mass never changes. No exceptions.
2H2 (g) + O2 (g) -->2H2 O(g)
mole ratio of H2:O2=2:1
7.25/2=3.625
Molar mass of oxygen gas:
O₂ = 16 * 2 = 32.0 g/mol
1 mole O₂ -------------- 32.0
9.05 mole O₂ ---------- ?
Mass = 9.05 * 32.0
Mass = 289.6 g of O₂
hope this helps!
50% - you have two bb pairs
