Flue gas problem solving needed pt.2

Question

Hi,

Can anyone help me with these excercises.

The car consumes octane 8 liters per 100km (8l/100km). How to calculate 80 km journey's exhaust fumes total mass.

Octane's density is 0.75 kg/dm3

The combustion reaction is 2 C8H18 + 25 O2 => 16 CO2 + 18 H2O

Answer 1

8 liters octane/100 km x 80 km = 6.4 liters of octane consumed

mass of octane consumed = 6.4 liters x 0.75 kg/liter = 4.8 kg octane (note 1 dm3 = 1 liter)

moles of octane consumed = 4.8 kg octane x 1000 g/kg x 1 mole/112 g = 42.86 moles octane

mass of CO2 produced = 42.86 moles octane x 16 moles CO2/2 moles octane x 44 g CO2/mole CO2 = 15,087 g CO2

mass H2O produced = 42.86 moles octane x 18 moles H2O/2 mol octane x 18 g/mole = 6943 g H2O

Total mass of exhaust gas = 15087 + 6943 = 22,030 grams = 22,00 grams (to 2 significant figures)