AQA A2 CHEM4 & CHEM5 June 2015 [official discussion thread]

Does anyone know why you have to square root KC in June 13 Chem4 2biii ? Got units right, but slightly confused on answer.

Thanks in advance.

Ok from Q2b)i) you'll have your K_c equation to be:

Now when you get to Q2b)iii) a new equation is given to you.

NOCl_(g) ⇌ NO_(g) + ½Cl_2(g)

From here you should form a new K_c equation which should look like this:

You should notice that the powers in this equation has been multiplied by ½ when compared to the fist K_c equation.
This implies that the initial K_c equation has been multiplied to a power of ½.

Hence why you must do √(7.4 × 10^–3).

I hope that helps. :smile:

(edited 9 years ago)

Question: why, in the titration of Fe2+ with dichromate (6) ions, is the end product orange...because the titration produces Cr3+ ions which are green, however every book I look in says the end is orange

Reply 382

Cobalt_

21

Chemistry University student here.

Got an A* in chemistry (AQA) if anyone has any questions about A2 Chemistry let me know.
Always happy to help.

Good luck to everyone!
You guys/girls will be fine c:

Reply 383

TheGemini

10

Original post by Cobalt_

Chemistry University student here.

Got an A* in chemistry (AQA) if anyone has any questions about A2 Chemistry let me know.
Always happy to help.

Good luck to everyone!
You guys/girls will be fine c:

Would you recommend doing 1 past paper more than once?

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Reply 384

Cobalt_

21

Original post by TheGemini

Would you recommend doing 1 past paper more than once?

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Yup, I redid a few.

I recommend doing old spec past papers too!!

Reply 385

username607202

17

Original post by TheGemini

Would you recommend doing 1 past paper more than once?

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Do every past paper you can get your hands on, and then redo them! Rinse and repeat.

Reply 386

TheGemini

10

Original post by Cobalt_

Yup, I redid a few.

I recommend doing old spec past papers too!!

Thankyou

well done on your A* btw :biggrin:

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Reply 387

TheGemini

10

Original post by Wick3d

Do every past paper you can get your hands on, and then redo them! Rinse and repeat.

Haha "Rinse and repeat" yessir!!! :biggrin:

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Reply 388

Cobalt_

21

Original post by TheGemini

Thankyou

well done on your A* btw :biggrin:

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No problem, only repeat them if you have forgotten most of them and or you dont have much else to do! c:

Reply 389

Thebest786

2

Yes, I understand now. Thank You.

Reply 390

Thebest786

2

Original post by TheGemini

The number of moles of new stoichiometric equation is 1/2 that of the previous stoichiometric equation .So the answer is (old Kc) to the power of a 1/2 which is square root of Kc

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Thanks!

Reply 391

Disney0702

9

Original post by Cobalt_

Chemistry University student here.

Got an A* in chemistry (AQA) if anyone has any questions about A2 Chemistry let me know.
Always happy to help.

Good luck to everyone!
You guys/girls will be fine c:

Hi there!

What did you do to help get your A* and did you find A2 Chemistry challenging during your A Level course?

I hope you don't mind my asking as to which University you attend and why you decided to do Chemistry at University?

Reply 392

Cobalt_

21

Original post by Disney0702

Hi there!

What did you do to help get your A* and did you find A2 Chemistry challenging during your A Level course?

I hope you don't mind my asking as to which University you attend and why you decided to do Chemistry at University?

What helped me get the A*?
- I used ChemRevise notes, made sure i knew the content fully. I pretty much knew the notes from memory aha. Then I moved on to past papers, old spec first so I could get a feel of the papers and type of questions being asked. If I couldnt do a question and had to refer to notes it would show I dont know the content probably so I would go over the content again.
Then I started new spec past papers. I set myself an aim. The first paper I do; I must get at least a A/High B and then move up my 4 marks each paper.
Doing this caused me to get around 98ish in the 2013 series (last past paper available for me)
Thats all there is too it tbh, I wish there was a simple way but there isnt. Just learn the chemrevise notes and do past papers and you should get an A/A*!

Did I find it challenging?
-Tbh with you I found AS harder at the time, when I entered A2 I really started to enjoy chemistry and because of that I found it easy(ish)
I found A2 biology at lot mroe challenging.

Why you decided to do Chemistry at University?
- Really enjoyed it, wanted to learn more about chemistry. Amazing job prospects and I want to be a scientist so c:

Im glad I study chemistry, nearly finished first year and ive learnt so much and the labs are amazing!!!!

If you have anymore questions just let me know c:

Reply 393

katy1996

anyone done the a2 practical yet? we have been told basic details but any more information would be appreciated :smile:

Reply 394

Disney0702

9

Original post by Cobalt_

What helped me get the A*?
- I used ChemRevise notes, made sure i knew the content fully. I pretty much knew the notes from memory aha. Then I moved on to past papers, old spec first so I could get a feel of the papers and type of questions being asked. If I couldnt do a question and had to refer to notes it would show I dont know the content probably so I would go over the content again.
Then I started new spec past papers. I set myself an aim. The first paper I do; I must get at least a A/High B and then move up my 4 marks each paper.
Doing this caused me to get around 98ish in the 2013 series (last past paper available for me)
Thats all there is too it tbh, I wish there was a simple way but there isnt. Just learn the chemrevise notes and do past papers and you should get an A/A*!

Did I find it challenging?
-Tbh with you I found AS harder at the time, when I entered A2 I really started to enjoy chemistry and because of that I found it easy(ish)
I found A2 biology at lot mroe challenging.

Why you decided to do Chemistry at University?
- Really enjoyed it, wanted to learn more about chemistry. Amazing job prospects and I want to be a scientist so c:

Im glad I study chemistry, nearly finished first year and ive learnt so much and the labs are amazing!!!!

If you have anymore questions just let me know c:

I do something pretty similar to that.

Instead of ChemRevise I use my CGP Student Book for AQA A2 Chemistry to cover my understanding on content and then I move on to past papers, old and new.

Woah 98(ish) marks! Did you then get 100% UMS in June 2014?

Thanks for the advice and good luck with uni. :smile:

(edited 9 years ago)

Reply 395

missuniverse23

1

Original post by katy1996

anyone done the a2 practical yet? we have been told basic details but any more information would be appreciated :smile:

No, the teacher hasn't even told us our topic yet! Although I know task 1 is titration with buffer and task 2 just some observations with metals or something. Any help would be much appreciated.

Reply 396

Cobalt_

21

Original post by Disney0702

I do something pretty similar to that.

Instead of ChemRevise I use my CGP Student Book for AQA A2 Chemistry to cover my understanding on content and then I move on to past papers, old and new.

Woah 98(ish) marks! Did you then get 100% UMS in June 2014?

Thanks for the advice and good luck with uni. :smile:

Nope, Got 111 in both I think :frown:

Thank you!, Good luck with your alevels. You'll be fine c:

Reply 397

Itsmonique

2

Original post by Cobalt_

What helped me get the A*?
- I used ChemRevise notes, made sure i knew the content fully. I pretty much knew the notes from memory aha. Then I moved on to past papers, old spec first so I could get a feel of the papers and type of questions being asked. If I couldnt do a question and had to refer to notes it would show I dont know the content probably so I would go over the content again.
Then I started new spec past papers. I set myself an aim. The first paper I do; I must get at least a A/High B and then move up my 4 marks each paper.
Doing this caused me to get around 98ish in the 2013 series (last past paper available for me)
Thats all there is too it tbh, I wish there was a simple way but there isnt. Just learn the chemrevise notes and do past papers and you should get an A/A*!

Did I find it challenging?
-Tbh with you I found AS harder at the time, when I entered A2 I really started to enjoy chemistry and because of that I found it easy(ish)
I found A2 biology at lot mroe challenging.

Why you decided to do Chemistry at University?
- Really enjoyed it, wanted to learn more about chemistry. Amazing job prospects and I want to be a scientist so c:

Im glad I study chemistry, nearly finished first year and ive learnt so much and the labs are amazing!!!!

If you have anymore questions just let me know c:

Thanks for the advice. I totally agree with the fact that I found AS harder compared to A2. I think it's because at A2 I knew what to expect.
I'm aiming for an A overall in chemistry. I got a Low B is AS so I'm retaking unit 1 to boost my UMS marks. From the start of A2 I've been achieving A/A* in the tests for each topic. Although my weakest topic is structure determination.
If you don't mind me asking what did you get for the ISA/EMPA? Any advice as to how to do well?

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Reply 398

Itsmattyjayy

1

Hey guys, I just thought I'd share my notes because a few people have asked. I've basically been typing them and then explaining them to myself and I've made a few YouTube videos which should be helpful, they're really helping me! I'm hoping to have everything uploaded (unit 4 and 5) very soon. I will also attach the actual typed notes so you can print them when I get time.

http://www.youtube.com/playlist?list=PLRshP-45QuHOXr-8EzXmjeWfH0r9EQtC8

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Reply 399

Cobalt_

21

Original post by Itsmonique

Thanks for the advice. I totally agree with the fact that I found AS harder compared to A2. I think it's because at A2 I knew what to expect.
I'm aiming for an A overall in chemistry. I got a Low B is AS so I'm retaking unit 1 to boost my UMS marks. From the start of A2 I've been achieving A/A* in the tests for each topic. Although my weakest topic is structure determination.
If you don't mind me asking what did you get for the ISA/EMPA? Any advice as to how to do well?

Posted from TSR Mobile

Yeh, I got a lot higher in A2 than AS, you will be fine tbh.

In terms of the ISA/EMPA's
My school did EMPA's for both (we had to choose either the isa or empa for a2; I picked empa)
I got: AS: 58 and A2: 50 something (cant remember, was an A* though)

For A2, dont underestimate the experiment. The observations were tricky tbh, check for everything! temp change, ppt formation, solution colour change, effervescence etc etc.
I remember for mine there was a change in colour from blue to brown I think, but when I poured it down the sink it was yellow. Be careful of this, the solution may appear a different colour in the test tube. AQA accepted both answers but yeh just be careful.

In terms of the exams, I cant really give advice. They are based on your experiment so my advice is gonna be pretty invalid. Section A for A2/AS hardly changes though so look at the past papers and apply the same questions to your experiment. Its normally a titration calculation. So providing you can remember your average titre, you can bag like 20 marks from section A before you even do the exam!

Good luck, feel free to ask me anything else.