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Edexcel A2 Chemistry 6ch04/05 JUNE 2015

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Reply 620
Any tips on how to remember acid and base titration graphs? Thanks! ☺️
Reply 621
image.jpg
This is how I did q5. Work out kc of both then you can see that if you square kc of the 2nd equation you get kc of the first. Hope this helps.☺️
Reply 622


for question 12 the answer i think is B.
it cant be C or D as their is no chiral carbon present
it cannot be A as the priority groups are on opposite sides so that would be an E isomer
Reply 623
Original post by MeeraP07
do you happen to have a question to make the explanation a bit easier?


Hi, so a example would be: http://qualifications.pearson.com/content/dam/pdf/A%20Level/Chemistry/2013/Exam%20materials/6CH04_01_que_20130114.pdf
question 27)ii)

COuld you please show me your working behind it?
anyone have any advice on the main topics to look over from AS chemistry or how much of last years course should I know for unit 4 tomorrow. Thanks!
Original post by Leeki
image.jpg
This is how I did q5. Work out kc of both then you can see that if you square kc of the 2nd equation you get kc of the first. Hope this helps.☺️



Brilliant. Thank you very much :smile:

Original post by simsid
for question 12 the answer i think is B.
it cant be C or D as their is no chiral carbon present
it cannot be A as the priority groups are on opposite sides so that would be an E isomer


Can you explain more please? Not sure how to go about those type of questions at all.

So how do you know what the priority groups are? And how did you eliminate some options? Chiral carbon has 4 different groups yeah? How do you know that from the skeletal formula?
guys im really scared about soap making/ transesterificastion... also when they throw in random stuff like the june 2014 papr!!!

e=volume of solution */_\T* c

how was i suppoed to know you fonr convert to dmcubed!!!!!!!!!:angry:

so yeah guys do you have any resources or good techniques to do them (transesfterifcation/soap making)???

thank alot and good luck
Original post by madmenace
guys im really scared about soap making/ transesterificastion... also when they throw in random stuff like the june 2014 papr!!!

e=volume of solution */_\T* c

how was i suppoed to know you fonr convert to dmcubed!!!!!!!!!:angry:

so yeah guys do you have any resources or good techniques to do them (transesfterifcation/soap making)???

thank alot and good luck


page 14 https://chemrevise.files.wordpress.com/2015/06/5-further-organic.pdf
Has anyone done the June 2013 R paper that would mind answering a few questions? (:
Original post by Nautic4l
Brilliant. Thank you very much :smile:



Can you explain more please? Not sure how to go about those type of questions at all.

So how do you know what the priority groups are? And how did you eliminate some options? Chiral carbon has 4 different groups yeah? How do you know that from the skeletal formula?

image.jpg Hope this helps 👍👍
Reply 630
Original post by Nautic4l
Brilliant. Thank you very much :smile:



Can you explain more please? Not sure how to go about those type of questions at all.

So how do you know what the priority groups are? And how did you eliminate some options? Chiral carbon has 4 different groups yeah? How do you know that from the skeletal formula?


if you cant tell from the skeletal formula your just going to have to draw out the displayed formula.
priority groups are the groups either side of the double bond with the highest molar mass basically (this stuff was in AS so try and find some resources if your not sure.)
Reply 631
Can anyone please explain how a buffer solution works like with an example? 😥 I feel like that's gonna be one of the questions...everything I don't know always comes up.😥 thanks ☺️
Reply 632
Original post by goonieskellie
Has anyone done the June 2013 R paper that would mind answering a few questions? (:

I did that paper. I don't mind.
Reply 633
Original post by Leeki
Can anyone please explain how a buffer solution works like with an example? 😥 I feel like that's gonna be one of the questions...everything I don't know always comes up.😥 thanks ☺️
http://www.chemguide.co.uk/physical/acidbaseeqia/buffers.html
this is really useful.
Reply 634


Thanks ! ☺️😊
Original post by Leeki
I did that paper. I don't mind.


Ah ok awesome, they are quite simple questions i think but i just can't understand them aha!
11.b.i. how do you get to 0.05?
12.b. how do you know what the equivalence point is?
13.b.iv. i wrote 2.4 and 4.8 and i dont really understand why both the answers are 2.4. do you measure the distance between the half lives?

thankyou! i know most of them are probably really obvious lol :l
Original post by cathalmcc
image.jpg Hope this helps 👍👍


Perfect, thank you :smile:
http://qualifications.pearson.com/content/dam/pdf/A%20Level/Chemistry/2013/Exam%20materials/6CH04_01_que_20110126.pdf

Questions wrt Bronsted-Lowry acid-base like Q13, what do you guys look for immediately? I always get them wrong
Reply 638
At 100°C, pure water has a pH of 6, whereas at 25°C it has a pH of 7. This is because

A the dissociation of water is endothermic, so the concentration of hydrogen ions is lower at 100 °C than it is at 25 °C.
B the dissociation of water is exothermic, so the concentration of hydrogen ions is lower at 100°C than it is at 25°C.
C the dissociation of water is endothermic, so the concentration of hydrogen ions is higher at 100 °C than it is at 25 °C.
D at 100 °C, water has a higher concentration of hydrogen ions than of hydroxide ions.

the answer is C but how do you know that it would be C?
Reply 639
Original post by Nautic4l
http://qualifications.pearson.com/content/dam/pdf/A%20Level/Chemistry/2013/Exam%20materials/6CH04_01_que_20110126.pdf

Questions wrt Bronsted-Lowry acid-base like Q13, what do you guys look for immediately? I always get them wrong


I always look at what molecule has lost a hydrogen and which one has gained a hydrogen. the answer is A because the OH gains a CH3 group so this is not a acid base reaction

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