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# Converting delta G units Watch

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1. if delta G is 29500 J mol-1
would it be 29.5 kJmol-1 ?

If it was -657824.4 Jmol-1
would it be -658kJmol-1

I'm asking this because my revision guide says the first one is 295 and the second one is -65.8

2. 29 500 = 29.5 thousand (to 3sf)

657 824.4 = 658 thousand (to 3sf)
3. (Original post by kiiten)
if delta G is 29500 J mol-1
would it be 29.5 kJmol-1 ?

If it was -657824.4 Jmol-1
would it be -658kJmol-1

I'm asking this because my revision guide says the first one is 295 and the second one is -65.8

Revision guide is bogus
4. (Original post by AlexFam)
Revision guide is bogus

But its a CGP one
5. (Original post by kiiten)
But its a CGP one
CGP = Crap Guide, People ...
6. (Original post by kiiten)
But its a CGP one
It's also wrong
7. Nah, CGP ones are kinda good but you have to take the information with a bit of salt; try not to rely on it too much.
8. (Original post by kiiten)
But its a CGP one
Are you sure you read the question correctly? 0.7MJmol-1 is an awfully large energy change.
9. (Original post by alow)
Are you sure you read the question correctly? 0.7MJmol-1 is an awfully large energy change.
C=O bond energy in CO2 is about 802 kJ mol-1
10. (Original post by alow)
Are you sure you read the question correctly? 0.7MJmol-1 is an awfully large energy change.
Yeah ques 1.a)i) and 2.a)

- sorry its a bit dark :3
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11. (Original post by alow)
Are you sure you read the question correctly? 0.7MJmol-1 is an awfully large energy change.
I also have another ques - about born haber cycle for KBr.

So if you put KBr (s) at the bottom then on the left hand side (starting from the bottom going up) is it

K (s) + 1/2 Br2 (g)

then

K (g) + 1/2 Br2 (g)

(atomisation of metal)
12. (Original post by kiiten)
I also have another ques - about born haber cycle for KBr.

So if you put KBr (s) at the bottom then on the left hand side (starting from the bottom going up) is it

K (s) + 1/2 Br2 (g)

then

K (g) + 1/2 Br2 (g)

(atomisation of metal)
Bump

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13. Any chance you could draw what you're describing in terms of a Born Haber cycle and post a picture? It's quite hard to work out exactly what you mean by your description and a picture speaks 1000 words
14. (Original post by MexicanKeith)
Any chance you could draw what you're describing in terms of a Born Haber cycle and post a picture? It's quite hard to work out exactly what you mean by your description and a picture speaks 1000 words
Oh yeah of course - sorry its a bit messy

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15. (Original post by kiiten)
Oh yeah of course - sorry its a bit messy

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yes, although with BH it does not matter if you deal with the metal or the non-metal first.

Check out the Born Haber cycles on this page
16. (Original post by charco)
yes, although with BH it does not matter if you deal with the metal or the non-metal first.

Check out the Born Haber cycles on this page
So was I right to cross out the 1/2 and 2 on Br (see diagram)?
17. (Original post by kiiten)
So was I right to cross out the 1/2 and 2 on Br (see diagram)?
No, you were wrong.

Your first step is atomisation of potassium

Your second step is atomisation of bromine.
18. (Original post by charco)
No, you were wrong.

Your first step is atomisation of potassium

Your second step is atomisation of bromine.
Ah ok, thanks

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