Question

2.00 g of 1-propanol (C3 H8 O, molecular weight 60.10 amu) burns in excess oxygen according to the combustion reaction: 8pts 2 C3 H8 O (g) + 9 O2 (g) → 6 CO2 (g) + 8 H2 O (g) Compute (a) the mass of carbon dioxide produced and (b) the mass of oxygen consumed.

Answer 1

molar mass of C3H8O = 60 g/mol
number ofmole of C3H80 = (given mass)/(molar mass)
= 2.00/60
= 0.034 mole
reaction taking place is
2 C3 H8 O (g) + 9 O2 (g) → 6 CO2 (g) + 8 H2 O (g)
a)
according to reaction
2 mole of C3H8O give 6 mole of CO2
1 mole of C3H8O give 3 mole of CO2
0.034 mole of C3H8O give (3)*0.034 mole of CO2
number of mole of CO2formed = 0.102 mole

molar mass of CO2 = 44 g/mol
mass of CO2 formed = (number of mole of CO2)*(molar mass)
= 0.102*44
= 4.49 g

Answer : 4.49 g
b)
according to reaction
2 mole of C3H8O required 9 mole of O2
1 mole of C3H8O required 9/2 mole of O2
0.034 mole of C3H8O required (9/2)*0.034 mole of O2
number of mole of O2 required = 0.153 mole

molar mass of O2 = 32 g/mol
mass of O2 required = (number of mole of O2)*(molar mass of O2)
= 0.153*32
= 4.9 g

Answer : 4.9 g