OCR Chemistry A 2017 Exam Thread (New A Level)

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Original post by TheGreatPumpkin

Does OCR use 1atm=101kpa or 1atm=100kpa, I've seen both?

afaik both are acceptable :h:

:h:

Original post by BTECColouring

Cheers buddy, I personally thought the first chemistry and biology paper were both heavily A2 based. That could mean I've answered everything wrong tho... :frown:

:frown:

I don't really remember them! Is that bad?!

Hi- just to clarify are you saying that acyl chlorides are the most reactive/strongest??

I'm so done with chem

Original post by izzyp12345

Hi- just to clarify are you saying that acyl chlorides are the most reactive/strongest??

In contrast with anhydrides/carboxylic acids yes. They have vigorous reactions.

Original post by DoubleDoors

In contrast with anhydrides/carboxylic acids yes. They have vigorous reactions.

fab thankyou :smile:

:smile:

Has everyone finished recapping the content?

I predict nmr will be benzene related OR acid anhydride (I don't think they've asked nmr on acid anhydride)

Original post by Jitesh

I predict nmr will be benzene related OR acid anhydride (I don't think they've asked nmr on acid anhydride)

3 oxygen atoms in molecular formula? No HC-O environment? NICE ACID ANHYDRIDE OCR MATE x

Original post by LeeCKOC

Anyone else not feeling confident at all?

meeee, i've done loads of past papers and revision but still don't feel confident 😭😭

Original post by DoubleDoors

Relative reactivity, from strongest carboxylic acid derivative to weakest:
Acyl Chloride -> Acid Anhydride -> Carboxylic acid.

Another point while we're on it is that only anhydrides and acyl chlorides are strong enough to esterify phenol.

Did not know that :/

Is there any other conditions they have when they esterify phenol?

Original post by Nettled

Did not know that :/

Is there any other conditions they have when they esterify phenol?

No catalyst needed.

Help please! I don't understand how the structure of aspartic acid is found when all the questions says is its formula is R=CH2COOH?

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Original post by suki23

Help please! I don't understand how the structure of aspartic acid is found when all the questions says is its formula is R=CH2COOH?

Read one line above that, it tells you where R goes!

Original post by suki23

Help please! I don't understand how the structure of aspartic acid is found when all the questions says is its formula is R=CH2COOH?

It's an amino acid so you're expected to know that R is bonded to a carbon with an amine group, a hydrogen and a carboxylic acid group attached

Original post by DoubleDoors

Read one line above that, it tells you where R goes!

Thank you!

Original post by Jdc18

It's an amino acid so you're expected to know that R is bonded to a carbon with an amine group, a hydrogen and a carboxylic acid group attached

Thank you

Question 3 on Set 2 organic how is the answer A?

Original post by SGHD26716

Question 3 on Set 2 organic how is the answer A?

Sodium halide and H2SO4 produce a hydrogen halide.

The halide (:Br-) is a nucleophile and substitutes the -OH.

Original post by DoubleDoors

Sodium halide and H2SO4 produce a hydrogen halide.

The halide (:Br-) is a nucleophile and substitutes the -OH.

Why does it not also substitute the OH on COOH?

Also is benzene saturated or unsaturated?

Thanks for your time.

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