Question

Calculate the mass (in g) of O2 consumed in the complete combustion of 47.5 g sample of C4H8O. (Hint, write the balanced equation.)

Answer 1

molar mass of C4H8O = 72 g/mol
number of mole of C4H8O = (given mass)/(molar mass)
= 47.5/72
= 0.66 mole
reaction taking place is
2C4H8O + 11O2 -- > 8CO2 + 8H2O
according to reaction
2 mole of O2 required 11 mole of O2
1 mole of O2 required 11/2 mole of O2
0.66 mole of O2 required (11/2)*0.66 mole of O2
number of mole of O2 required = (11/2)*0.66
= 3.63 mole

molar mass of O2 = 32 g/mol
mass of O2 required = (number of mole of O2)*(molar mass of O2)
= 3.63*32
= 116.2 g

Answer: 116.2 g