Hi Borek. Thanks for replying.
So, I got them. Methane at -890.3 and Propane at -2219.1. Is it just a matter of solving for x in an equation like this:
-890.3x + -2219.1y = -776 kJ
And that will give me the moles of x, at which point I use the total moles I previously found to get the mole fraction?
y being (0.512-x),
so -890.3x + (-2219.1)(.512-x) = -776kJ
x = .27 mol / .512total moles = 53% CH4
Is that correct?
//edit: Incorrect. Got it wrong.
'supposed to be 42.7%. Don't know where that came from