Suppose that 0.250mol of methane, CH4(g), is reacted with 0.400mol of fluorine, F2(g), forming CF4(g) and HF(g) as sole products. Assuming that the reaction occurs at constant pressure, how much heat is released?

Question

Substance ΔH∘f (kJ/mol)
C(g) 718.4
CF4(g) −679.9
CH4(g) −74.8
H(g) 217.94
HF(g) −268.61

I ended up with the wrong answer can I ask what I did wrong?

So I got the dHrxn which I found to be -1,679.54

I then determined the limited reagent was indeed F2 and that it produced .1 mol of CF4

I then divided -1,679.54 by .1 to get -16,795.4 and converted it to kilojoules to be 16.8 (sig figs) but it was not right.

Answer 1

I think the -1679.54 is ok.
That's for 1 mol CH4. If you will note 1 mol produces 1,679 (is that J or kJ). Probably kJ. But then you correct for having only 0.1 mol and you obtained MORE? How can that be? If your number is for 1 mol and you have only 0.1 mol you must get only 0.1 of that much so
1679.54 (check that's kJ) x 0.1 = ?

Answer 2

I'll bet those values in the problem are in kJ/mol so no conversion to kJ is necessary.

Answer 3

This is still not correct. I do not know what I am doing wrong