How many grams of O2(g) are needed to completely burn 82.8g of C3H8

Balanced chemical reaction:-
C3H8(g) + 7O2(g) ---------> 3CO2(g) + 4H2O(g)

Molar mass of C3H8 = 44 g/mole
Thus, moles of C3H8 in 82.8 g of it = mass/molar mass = 82.8/44 = 1.882
Thus, as per the balanced reaction, moles of O2 required for complete combustion of C3H8 = 7*moles of C3H8 reacting = 7*1.882 = 13.173
Molar mass of O2 = 32 g/mole
Thus, mass of O2 reacting = moles*molar mass = 13.173*32 = 421.53 g