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greenglasses
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Homework Statement
Calculate the Electron Affinity of F(g) in kJ/mole using Hess' Law.
IE1 + IE2 of Sr(g) is 1580 kj
Hsub of Sr(s) is 144 kJ
Hdiss of F2 is 79 kJ
Hf of SrF2 (s) is -1215 kJ
Hlatt of SrF2 (s) is -2441 kJ
Homework Equations
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The Attempt at a Solution
1. Sr(g)+Sr+(g) -> Sr2+(g) + Sr+(g) + 2e-
2. Sr (s) -> Sr(g)
3. F2(g) -> 2F(g)
4. Sr(s) + F2(g) -> SrF2
5. Sr2+(g) + F-(g) -> SrF2 (s)
I tried to:
flip 5
1/2 * flip 3
flip 1
flip 2
copy 4
but when I did that, I ended up with an extra 1/2 F2 that I couldn't cancel out. I'm not sure what to do.