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# Cambridge Chemistry Challenge watch

1. Please; Any help with Gold? It´s very difficult...
2. With Gold, I have the mass of graphene per m^2 in kg and the surface area of the Earth, also in m^2. I'm multiplying them together, which isn't returning the correct result. What am I doing wrong?
3. (Original post by chemistinthemaking)
I'm using my molecular modelling set, It's getting fiddly! PM me if you have the figures thanks, I'll love you forever
Yeah i'm getting bored of this endless isomerism puzzle. someone put me out of my misery again.
4. (Original post by Lutski)
With Gold, I have the mass of graphene per m^2 in kg and the surface area of the Earth, also in m^2. I'm multiplying them together, which isn't returning the correct result. What am I doing wrong?
Hey, I'm doing this too. GRR Silly question... My eyes hurt. I give in, time to sleep and revise in the morning.
5. (Original post by Lutski)
With Gold, I have the mass of graphene per m^2 in kg and the surface area of the Earth, also in m^2. I'm multiplying them together, which isn't returning the correct result. What am I doing wrong?
What is the value of mass per meter squared you have?
6. someone help with Rg pleaseeeeeee pm me
7. (Original post by chemistinthemaking)
someone help with Rg pleaseeeeeee pm me
Same, on this one I really have not got a clue

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8. Help in Gold; I know that SA of Earth is 510064471.9 km^2 and of graphene: 2.675*10^-3 km^2/kg. But I can´t get the correct answer
9. For those of you stuck on Rg. A clue is that there can only be one element in the centre and the shape of the molecule is drawn in the back ground. For 2nd one, it might help to find the different combinations of the two "poles" of the molecule as they have different bond angle. Then assess the different combinations for the 3 elements in the middle.
10. Can someone give me the answer to Rg? I'm not sure I actually have the knowledge to complete this.
11. (Original post by Lutski)
Can someone give me the answer to Rg? I'm not sure I actually have the knowledge to complete this.
same
12. can somebody private message me with some help with the Rg! seriously struggling with it!
13. (Original post by distroyer)
can somebody private message me with some help with the Rg! seriously struggling with it!
Same, I have holes in my knowledge to complete this

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14. someone tell me Rg and I will be soooo grateful. pm me pleaseeeee I need to study for my exam as well
15. For the first compound, only Si can be in the middle, for the second one, only P in the middle and for the last one, only S in the middle. From there, it's just the number of different permutations you can have which would result in optical isomers.
This is a massive clue for the last molecule:
http://en.wikipedia.org/wiki/Octahed...cular_geometry
16. so it's 1 + something^2 plus 30^3?
17. This makes me sad, I feel as if I can't do anything at all.
18. I still dont get it with Rg... :/ I thought abt 30^3 + 1 + something^2 too.....
19. There's more than one isomer for the first one - it's chiral...

As for the second one, use the fact that you know the 3rd is 30. Compare the number of different ligands to the number if isomers.
20. (Original post by chemicangel)
There's more than one isomer for the first one - it's chiral...

As for the second one, use the fact that you know the 3rd is 30. Compare the number of different ligands to the number if isomers.
Thanks! I got it

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