AQA CHEM2 2nd June 2015 [Official thread]

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Original post by future doctor x

Here is the table that is on the back of the periodic table we are given in the exam

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Ty! In ocr,we don't get the carbon carbon double bond value .Now I see that,I can answer part i, but others have done it so no point now.
Ty for the pic though!

Reply 422

future doctor x

2

Original post by Kadak

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Where did the c=o come from?

Look at the attachment C=O is the functional group of an aldehyde and a ketone

Reply 423

future doctor x

2

Original post by Kadak

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Ty! In ocr,we don't get the carbon carbon double bond value .Now I see that,I can answer part i, but others have done it so no point now.
Ty for the pic though!

Oh okay u do Ocr bt isnt this thread for aqa students ? And it must be different mustn't it ?

Reply 424

Original post by future doctor x

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Where did the c=o come from?

Look at the attachment C=O is the functional group of an aldehyde and a ketone
Yeah,I just remebered.Thanks for the pic.

Reply 425

Original post by future doctor x

Oh okay u do Ocr bt isnt this thread for aqa students ? And it must be different mustn't it ?

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I Have the AQA book.Nothing wrong with helping others across exam boards.There isn't much differences, but for wavenumber and bonds you guys get wayy more than we do

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Reply 426

Protoxylic

14

Original post by Kadak

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I Have the AQA book.Nothing wrong with helping others across exam boards.There isn't much differences, but for wavenumber and bonds you guys get wayy more than we do

Slight differences with the wave numbers. N.m.r. chemical shift data is widely different across exam boards, so I would be careful in using the OCR data sheet with AQA questions.

Reply 427

kandykissesxox

21

Original post by Kadak

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Where did the c=o come from?

Hey i'm so sorry I went to eat :colondollar:

But yes we are given values for the c=o bond

Reply 428

Original post by Protoxylic

Slight differences with the wave numbers. N.m.r. chemical shift data is widely different across exam boards, so I would be careful in using the OCR data sheet with AQA questions.

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Why are there different values.Surely science has a standardised set of values all chemists use?

Reply 429

kandykissesxox

21

Original post by Kadak

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Why are there different values.Surely science has a standardised set of values all chemists use?

This is what we're given, I'm still unsure :frown:

Reply 430

Original post by kandykissesxox

This is what we're given, I'm still unsure :frown:

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Nvm the c=o,but it's spectrum 2 as only that one has the peak around 1620-1680.If you look closely at spectrum 1, the peak isn't there for the c=c double bond.

Reply 431

Sexybadman

17

Yo can anyone explain aldehydes and ketones to me, like where the O-H goes and double bond goes, Im struggling a lot...
Any more info you could give around around this topic I'd be grateful cheers :wink:

Reply 432

kandykissesxox

21

Original post by Kadak

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Nvm the c=o,but it's spectrum 2 as only that one has the peak around 1620-1680.If you look closely at spectrum 1, the peak isn't there for the c=c double bond.

ah, i see thank you :smile:

Reply 433

Original post by kandykissesxox

ah, i see thank you :smile:

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Welcome 😃.

Reply 434

Guls

14

Original post by Sexybadman

Yo can anyone explain aldehydes and ketones to me, like where the O-H goes and double bond goes, Im struggling a lot...
Any more info you could give around around this topic I'd be grateful cheers :wink:

Yo! There's isn't a C-O bond in either aldehydes or ketones but there is a C=O present. This carbonyl group has to be in the middle (not ends) to make a ketone but if it is on the end then it's a aldehyde.

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(edited 8 years ago)

Reply 435

Original post by Sexybadman

Yo can anyone explain aldehydes and ketones to me, like where the O-H goes and double bond goes, Im struggling a lot...
Any more info you could give around around this topic I'd be grateful cheers :wink:

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Aldehydes have The general form RCHO,with there always being a C=O.Any aldehyde will have al at the end e.g ethanal .There is a dirty trick to remember that if you can see it.
Ketones have the general formula R2CO,but usually it's three Carbon atoms bonded together (single) with the middle carbon having a double bond with a oxygen. Any ketone has anone as it's end e.g. Propanone.

Reply 436

Original post by Sexybadman

Yo can anyone explain aldehydes and ketones to me, like where the O-H goes and double bond goes, Im struggling a lot...
Any more info you could give around around this topic I'd be grateful cheers :wink:

Posted from TSR Mobile

You get aldehydes when oxidise a primary alcohol under distillation with [O].
You get a aldehyde when you oxidise a secondary alcohol under reflux with [O].
For both usually acidified k2CR207 is used,although it's really CR207 with a 2 - charge,the charge coming from any element in front of CR207.

(edited 8 years ago)

Reply 437

Protoxylic

14

Original post by Kadak

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You get aldehydes when oxidise a primary alcohol under distillation with [O].
You get a aldehyde when you oxidise a secondary alcohol under reflux with [O].
For both usually k2CR207 is used,although it's really CR207 with a 2 - charge,the charge coming from any element in front of CR207.

*** Acidified K2Cr2O7. It has to be acidified for the oxidation to take place.

Reply 438

akereem100

10

Question 6 b june 2013 The questions was in bright sunlight chlorine reacts with water to form oxygen as one of the products. Write an equation for this reaction. :angry:

I thought Cl2 reactions with water will produce HCLO

Spoiler

Reply 439

kattoo

It reacts differently when bubbled through water in bright sunlight and without bright light, so there's 2 different equations to learn unfortunately :frown: