chem question!!!!!!!! urgent

[LOLZ]

what mass of air (which is 23.2 % O₂(g) and 75.5% N₂(g) by mass) would be needed to burn 1.0 kg of gasoline (octane, C₈H₁₈)? The gasoline combines with oxygen gas to form CO₂ and water.

[jaelen]

C₈H₁₈ +(25/5)O₂ = 8CO₂ + 9H₂₀

1 kg octane = 8.77 mol

8.77*(25/2)=109.65 mol O₂ needed, which is 3.407 Kg

now we do a simple ratio calculation ((3407g*100)/23.2)= 14.688 Kg


So you will need about 14.7 Kg air

Hope that helped