Re: CSSA Chemistry 2011
How did people do the octane question???
This is how I went about doing it..
They provided us with the octane density e.g. 780g/L and they also provided us with the molar mass e.g. 144g/moL
So I said, in 1L of octane there is 780g of octane. No. of mols of octane = m/M = 780/144 = what ever the answer is.
And then the next question was like... how much energy is released from 1L of octane.
I then used my answer from part i) the no of mols of octane in 1L
In the equation it provided us a energy value e.g. 5000kJ/mol
so I just did 5000/no. of mols of octane in 1L
Next part I did a similar thing to ethanol e.g. got the no. of mols in 1L by doing the same method.
Then I did ratios ... e.g. ___no. of mols of octane = ____kJ = 10km
therefore this ____no. of mols of ethanol = _____kJ = how ever long.