Help with a 1/2 Gas Q?

[Andiio]

If propane is burnt in a limited amount of oxygen the poisonous carbon monoxide is formed as well as water vapour, so propane heaters must operate under conditions where oxygen supply is plentiful. When 5.35 L of propane gas is burnt at a temperature of 0 degrees C and a pressure of 760 mmHg in limited oxygen:

a) What volume of carbon monoxide is produced at the same temperature and pressure?

b) What volume of oxygen is used up in the reaction?




I'm not sure whether my method is correct.. but I don't know how else to do it :S
- What I did was, I wrote the equation;
2C₃H₈ (g) + 7O₂ (g) -> 6CO (g) + 8H₂O (g)

Then for a), I just did 5.35 L x 6/2 (the mol ratio) = 16.05 L
and for b), I did 5.35 L x 7/2 (mol ratio) = 18.725

..Which do yield the same answers, (except for a, the answer is 16.01 L)...

Help please!!!