Which volume of oxygen, at room temperature and pressure, is needed for complete combustion
of 1.0mol of methylpropan-1-ol?
a 108dm3 b 144dm3 c 156dm3 d 288dm

The molecular formula of methylpropan-1-ol is C4H10O, so the complete combustion equation is: C4H10O + 6O2 --> 4CO2 + 5H2O.  This mean to completely combust 1.0mol of methylpropan-1-ol, 6 mol of O2 is required. Molar mass of O2 is 32 g/mol, so 32g/mol x 6mol = 192 g of O2 is required.  At room temperature and pressure, the density of O2 is 1.3315 g/L (this can be obtained by density of gas = P/RT).  So the volume of O2 = mass/density = 192g/1.3315(g/L) = 144 L = 144 dm3. The answer is B.

The air is going to come out because of the low pressure.