The Chemistry A2-Level Thread 2014-2015

Reply 40

Hectors

5

Original post by Hudl

Thank you

, do you understand the question that was above this? or is that not on your spec?

No, sorry, I'm doing OCR A :smile:

Reply 41

Adami97

1

Im so tired of chemistry! 😱😱😱😱😱

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Reply 42

TheBlueBiro

15

Original post by Adami97

Im so tired of chemistry! 😱😱😱😱😱

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Same, there's just so much to remember and it's so easy to get confused it's depressing. :frown:

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Reply 43

cerlohee

16

Joining this thread! I got 268/300 with Edexcel last year.
So far we've covered kinetics, nmr and entropy, but we're starting the hard topics now D:
How're other edexcel people finding things? :smile:

Reply 44

Nat_LPS

15

Dudes any advice on to remember all the organic stuff like conditions and pracs. We're not even a third into organic and they're flooding my head and leaking out of my eyes with the tears. :tongue:

Reply 45

cerlohee

16

Original post by Nat_LPS

Dudes any advice on to remember all the organic stuff like conditions and pracs. We're not even a third into organic and they're flooding my head and leaking out of my eyes with the tears. :tongue:

How did you remember it all last year?
My teacher recommended drawing a massive A2 mind-map type thing in which you show all organic reactions that you come across. It may take a while to sort out how you'll do it, but it really cleared things up in my head last year. And if I ever forgot a reaction, visualizing its position on my mind map helped me to remember it!

Reply 46

Nat_LPS

15

Original post by cerlohee

How did you remember it all last year?
My teacher recommended drawing a massive A2 mind-map type thing in which you show all organic reactions that you come across. It may take a while to sort out how you'll do it, but it really cleared things up in my head last year. And if I ever forgot a reaction, visualizing its position on my mind map helped me to remember it!

There was a little less last year :tongue:

I see I haven't tried that yet thanks :smile:

Reply 47

ojj_12

8

Original post by Hudl

Can someone please help me word this answer to get 3 marks everytime. Its a nomenclature question where it is basically asking you to explain how a racemic mixture of the 2 steroisomers of a substance is formed.

The markscheme is
1) Carbocation
2) Planar
3) Equally as likely to form a bond on either side

I cant put the cation and planar into a smooth short sentence to get the overall 3 marks.

Before I checked the markscheme my answer was along the lines.

A racemic mixture of the 2 stereoismers of 2-chlorobutane is formed as when the hydrogen forms a bond using the electrons from the double bond, it is completely random and is equally likely to attach to the left or the right of the double bond meaning the carbocation intermediate could is equally likely to be on either side.

I cant fit in planar now though looking at the markscheme and my answer is to long any help?

I would say the carbocation on the C=O bond has an equal chance of being attacked by a nucleophile from either above or below, forming a racemate containing equal moles of enantiomers.

I don't know if it works for your exam board but it usually gets me the mark for AQA :smile:

Reply 48

ThePhoenixLament

18

Think I'm the first one doing OCR Salters B (especially as the spec isn't up on the thread) so far but at least it means you aren't doing this horrific coursework! Then again most boards probably have coursework in some way.

Reply 49

Hectors

5

Original post by ThePhoenixLament

Think I'm the first one doing OCR Salters B (especially as the spec isn't up on the thread) so far but at least it means you aren't doing this horrific coursework! Then again most boards probably have coursework in some way.

Our school dropped the Salters course because of that horrific coursework

Reply 50

little_green_man

Original post by apple_byte

I achieved a grade C in chemistry at AS, but then achieved an overall grade A at the end of A2. I missed an A* by 13 ums.
I did resit chem1 and chem 2.

So anyone who has questions ask away. I'll be happy to give advice to anyone who needs it.

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hey, I got a C in my AS chemistry as well. My F322 paper was a C and my F321 paper was a B. So i am only retaking F322. Can I ask you what are your strategies in improving so much that by the end of A2 you managed to achieve an A? It would be much appreciated if I could have some tips from you as I am sitting my mocks this week and have the actual exams in 3 months time. Thank you!

Reply 51

Keith.

Does anyone have the June 2014 Paper for Chem 5? :smile:

Reply 52

cerlohee

16

Original post by Keith.

Does anyone have the June 2014 Paper for Chem 5? :smile:

Which exam board? pm me your email address if edexcel

Reply 53

Hudl

OP

16

Does anyone have the AQA CHEM5 June 2014 paper not that I will be needing it until after the mocks anyway but my teacher takes a piss for eg with CHEM4 we only did section A of the CHEM4 Jun 14. I have not seen section B till this day

Reply 54

Keith.

Original post by cerlohee

Which exam board? pm me your email address if edexcel

AQA!

Reply 55

duckcrazy123

9

Could someone please help me, which direction would equilibrium shift in if there was:
•increase in temperature
•increase in pressure
•increase in concentration
Any help would really be appreciated
Thanks

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Reply 56

Hectors

5

Original post by duckcrazy123

Could someone please help me, which direction would equilibrium shift in if there was:
•increase in temperature
•increase in pressure
•increase in concentration
Any help would really be appreciated
Thanks

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Well, thinking about chatelier's principle increasing the temperature of the system favours the endothermic reaction as the system reacts in order to minimise the temperature change. This is true because if you look at the equilibrium constant Kc it will vary with temperature.
An increase in ppressure also shifts the equilibrium, favouring the reaction which produces less moles, also to counter this pressure change.
As the Kc value doesn't change with equilibrium, if you increase the concentration of a reactant the equilibrium shifts to counter this change accordingly.

The Chemistry A2-Level Thread 2014-2015

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