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AS Chemistry- helping each other out!

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Original post by NotoriousS
What's the R paper? any difference?


its a replacement paper it is harder and I have not revised anything yet
Original post by Rstlss
yeah?


how are you revising for tomorrow
any prediction from anyone about tomrorows unit 1 paper edxcel
Original post by SLRR
Did anyone else think the AQA EMPA was really really hard?


Yeah, it was really hard... No idea what I put for some of my answers, just made them up on the spot... Good luck me :frown:
Who's on AQA here? Predictions would be appreciated :smile:
Could someone help me with this question please? http://gyazo.com/5b8aca37091d74dc3e68fdb651e64a05

Answers are SO4^2 and ClO2^- but I don't understand how this corresponds with the oxidation numbers..could someone help pls?
If they give you a random Alkane and say what process can be used to obtain so so from it, how do you know if the answers fractional distillation or cracking? are they done on different types of hydrocarbons or is it just about what your trying to obtain
Original post by Shadowfire123
how are you revising for tomorrow


gonna go through all the past papers and do lots of questions
Original post by Rstlss
gonna go through all the past papers and do lots of questions


ohh good im gonna trying IAL jan 2014 and juen 2014 paper now
Can someone please help??
Aluminium chloride has a relative molecular mass of 267 in the gas phase.Deduce the formula of the aluminium compound that has a relative molecular massof 267 (1 mark)


5 (d) Deduce the name or formula of a compound that has the same number of atoms, thesame number of electrons and the same shape as the AlCl4− ion.
Hey I have a question about electron configuration. When should you use 1s(2) 2s(2) 2p(6) 3s(2) 3p(6) 3d(10) 4s(2) 4p(6)... And when should you use 1s(2) 2s(2) 2p(6) 3s(2) 3p(6) 4s(2) 3d(10) 4p(6)...
can anyone help me on jan 2014 IAl unit 1 edexcel chemistry Question 9 10 11 12 multiple cjoice wih the method please
Original post by Dyl98an
Hey I have a question about electron configuration. When should you use 1s(2) 2s(2) 2p(6) 3s(2) 3p(6) 3d(10) 4s(2) 4p(6)... And when should you use 1s(2) 2s(2) 2p(6) 3s(2) 3p(6) 4s(2) 3d(10) 4p(6)...


are you asking what element it is used for
Original post by Dyl98an
Hey I have a question about electron configuration. When should you use 1s(2) 2s(2) 2p(6) 3s(2) 3p(6) 3d(10) 4s(2) 4p(6)... And when should you use 1s(2) 2s(2) 2p(6) 3s(2) 3p(6) 4s(2) 3d(10) 4p(6)...


It doesn't matter which one you use. Unless in the exam they specifically tell you to do it in the order they are filled (which would be the 4s first), they will give the marks for any order.
Original post by Shadowfire123
are you asking what element it is used for


No in general. Because sometimes the 3d orbital comes after. How would you know when to write 3d after 4s2
Hi I was just wondering - are we allowed to discuss the papers as soon as they're out? Or are the rules same as GCSE (where they have international students still haven't sat them)?
Original post by Dyl98an
No in general. Because sometimes the 3d orbital comes after. How would you know when to write 3d after 4s2


you can before of after 4s
Original post by Dyl98an
No in general. Because sometimes the 3d orbital comes after. How would you know when to write 3d after 4s2


It doesn't matter, stylistically I think it looks better 4s^2 3d^10 if there are no p orbital electrons and better 3d^10 4s^2 4p^6 f there are. But yeah, it shouldn't matter the mark schemes will have both, and I don't think I've seen any elements heavier than zinc in a past paper (other than the halogens and group 2, but we weren't asked for electronic structure!)
In edexcel AS, do we need to know how to construct a born haber cycle?
Original post by itsConnor_
Could someone help me with this question please? http://gyazo.com/5b8aca37091d74dc3e68fdb651e64a05

Answers are SO4^2 and ClO2^- but I don't understand how this corresponds with the oxidation numbers..could someone help pls?


You know that it's going to be SOx2- (where x is undefined). The oxidation state of S is six, and the overall charge is 2-. Oxygen is usually 2-, so (+6) + x(-2) = -2 ... x = 4. I hope that helps.

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