Chemistry Help

collisster · 19 Sep 2009 at 23:14

Just doing some chemistry homework.. got stuck with this question, wondering if anyone could help me out please?

If 1dm^3 of petrol weighs 750g, what mass of CO2 is produced for each 1dm^3 burned?

C8H12 + 12.5 O2 ------>>>> 8CO2 + 9H2O

I've given it a go and fot that 750g of petrol is 6.58 moles, and then the 1:8 ratio gives 52.68 moles of CO2, mass = moles x Mr = 2317 odd grams of Co2 which is daft.

Cheers
Collisster

collisster · 19 Sep 2009 at 23:23

A level

collisster · 20 Sep 2009 at 00:00

platinum87 said:
writing an equation with 0.5 oxygen molecules is wrong

no its not, your not saying you've got .5 of a molecule of oxygen your talking about the number of moles.

I must have written the formula of the petrol down wrong and have redone the calculation and got 2444g CO2.

cheers for your help

collisster · 20 Sep 2009 at 00:06

well its c8h12 which is where I went wrong for a start. you can have either. both will give the same answer

collisster · 21 Sep 2009 at 12:30

I want to use c8h18 by the way, which is petrol, not c8h12 which isn't
my answer finally came out to 2315.8 which is for the c8h18 by the way