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# Official OCR AS Chemistry B (Salters) 27th May 2016 (new specification)

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1. For the final calculation question about UVA's frequency and breaking a bond with enthalpy 320kJ/mol ( I think that's what it is), I'm pretty sure you're meant to calculate the frequency of energy required to break a bond with enthalpy of 320kJ/mol, and see if it's above or below the frequency of UVA. However, I did it the other way round and found the bond enthalpy that UVA is able to break... would I still get the marks, do you think?
2. what molecule was non- polar in the multiple choice question?
3. Whatvdid you guys get for the Zn salt question at the beginning?
4. (Original post by katherine21678)
Whatvdid you guys get for the Zn salt question at the beginning?
I've that you need to filter it under reduced pressure and then heat the salt or use anhydrous salt
5. (Original post by Hariss)
what molecule was non- polar in the multiple choice question?
I think I put BF3, as it's symmetrical so the dipoles cancel out?
6. (Original post by Jatman01)
I've that you need to filter it under reduced pressure and then heat the salt or use anhydrous salt
yess! I put the same
7. Is anyone able to put together an unofficial mark scheme by any chance? Thanks!
8. (Original post by Dandie12)
what about the last question for the number of molecules
It was the ideal gas equation pV=nRT where p is pressure in kelvins, V is volume in m^3 (so you had to convert cm^3 to m^3), n is number of moles, R is gas constant and T temp in kelvins. You had all the info except moles where you then divide this value by avagadros constant to get number of molecules.
9. (Original post by Tommann1125)
Did you have to leave the volume of chlorine produced calculation in standard form?
11000?
10. (Original post by Hariss)
what molecule was non- polar in the multiple choice question?
I put CH2CL2 because the dipoles cancel
11. (Original post by Shan_non)
I put CH2CL2 because the dipoles cancel
no they don't. chlorine is more electronegative
12. (Original post by Dandie12)
11000?
Yeah I got that but was it meant to be like 1.1x10^4?
13. (Original post by Tommann1125)
Yeah I got that but was it meant to be like 1.1x10^4?
ah **** well then thats a mark dropped
14. (Original post by Tommann1125)
Yeah I got that but was it meant to be like 1.1x10^4?
11000 is 1.1x10^4
15. (Original post by faxingstar)
It was the ideal gas equation pV=nRT where p is pressure in kelvins, V is volume in m^3 (so you had to convert cm^3 to m^3), n is number of moles, R is gas constant and T temp in kelvins. You had all the info except moles where you then divide this value by avagadros constant to get number of molecules.
wouldn't you times by avagadro's constant?
16. (Original post by Dandie12)
wouldn't you times by avagadro's constant?
Yes, youre right I got that wrong. I feel like more time should have been given for that paper as i had to rush the last page in the final 10 minutes and then didnt get time to actually think and check my answers for mistakes. Did anyone else feel like this?
17. (Original post by faxingstar)
Yes, youre right I got that wrong. I feel like more time should have been given for that paper as i had to rush the last page in the final 10 minutes and then didnt get time to actually think and check my answers for mistakes. Did anyone else feel like this?
yeah it was quite a stretch for time
18. (Original post by faxingstar)
11000 is 1.1x10^4
Yes I'm fully aware of that? I'm saying was it meant to be left in standard form
19. (Original post by Hariss)
what molecule was non- polar in the multiple choice question?
I wrote chcl3 good knows why. i thought they cancel out
20. I made so many mistakes I'm really hoping for a B

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