Question

Which volume of oxygen, at room temperature and pressure, is needed for complete combustion

Answer 1

To determine the volume of oxygen needed for the reaction, we need to know the chemical formula of the fuel in order to know the chemical reaction.  Methylpropan-1-ol has a formula of C4H10O. The chemical reaction would be:

C4H10O + 6O2 = 4CO2 + 5H2O

We calculate volume as follows:

1 mol C4H10O ( 6 mol O2 / 1 mol C4H10O) ( 22.4 L O2 / 1 mol O2) = 134.4 L O2 needed or 134.4 dm^3

Therefore, the closest value would be B, 144 dm^3.

Answer 2

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.