OF2(g) + H2O(g) -> O2(g) +2HF(g) ΔH°rxn = -318 kJ

Question

Using bond energies, calculate the bond dissociation energy of the O-F bond, in OF2.

This is the question and I got 438 as the answer, which is wrong. I don't know what I did wrong??

Answer 1

If you will post your work I'll try to find the error. I found numbers in my book and you might check what you used. If I didn't skip a line, I read
O=O = 498
O-H = 464
HF = 569
Your numbers may differ since we aren't using the same text (I sure of that) but they should be close.

Answer 2

So I have
O=O = 498
O-H = 436
HF = 565

-318 = (x+436) - (498+565)
Since reaction=broken-made

-318 = x+436 - 1063

745 = x + 436

x= 309

Isn't this what you are supposed to do? :(