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OCR F324-June 2013 Chemistry

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perhaps someone can help me with this

1. Benzoicacid and phenylmethanol will react with each other in the presence of asuitable catalyst.
(i) Statea suitable catalyst for this reaction.
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[1]

Reply 401

otrivine

Original post by Zzzyax

concentrated H2SO4?

Reply 402

Plato's Trousers

Original post by otrivine

concentrated H2SO4?

dilute H₂SO₄

Reply 403

otrivine

Original post by Plato's Trousers

dilute H₂SO₄

Really, in our book its always concentrated! why is it dilute

Reply 404

Jodie_668

Original post by Plato's Trousers

dilute H₂SO₄

My teacher and book tell me that it is concentrated :confused:

Reply 405

otrivine

Original post by Plato's Trousers

dilute H₂SO₄

Dr Stuart, why is ClCH2CH2CL

only have a singlet , Should it not be pentet?

Reply 406

ZakRob

Original post by otrivine

Really, in our book its always concentrated! why is it dilute

Original post by Jodie_668

My teacher and book tell me that it is concentrated :confused:

Original post by Plato's Trousers

dilute H₂SO₄

To form an ester from an acid and alcohol it is most definitely catalysed by conc sulfuric acid. This is because this is a reversible reaction and you can hydrolyse the ester by using a dilut acid, hence why a conc acid is used to favour the forward reaction: esterification

Hope this clears things up.
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Reply 407

ZakRob

Original post by otrivine

Dr Stuart, why is ClCH2CH2CL

only have a singlet , Should it not be pentet?

If you dont mind me answering, I wanna test my understanding. The protons in the molecule are all in the same proton environment, hence there are no neighbouring 'different'
Protons. so therefore using the n+1 rule, 0+1= 1 so it is a singlet
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(edited 11 years ago)

Reply 408

otrivine

Original post by ZakRob

Correct!

Reply 409

Jodie_668

Original post by ZakRob

Thanks!

Reply 410

otrivine

Is there a mistake on question 6 on page 105 , compound E, there has to be 1 triplet as well because CH2 is present so if you add one , there should be 3?

Reply 411

Jake 94

Does anybody by any chance have a copy of the January 2013 F324 question paper and mark scheme?

Reply 412

otrivine

Original post by MathsNerd1

Thanks, also just going to warn you now, at 9 I'll be stopping to do some unit 1 revision. But that's 45 minutes from now so it's all good :smile:

It's question 7 (4)

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You got the question

Reply 413

MathsNerd1

Original post by otrivine

Is there a mistake on question 6 on page 105 , compound E, there has to be 1 triplet as well because CH2 is present so if you add one , there should be 3?

This is to answer your question.

The problems with kekules structure are that it failed to explain the chemical and physical properties of benzene fully. Mainly being benzene's low reactivity because if carbon carbon double bonds were present then it would react in a similar way to alkenes mainly expecting to decolourise when reacting with bromine water. But this doesn't happen. So the structure had to be refined to account for this property.

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Reply 414

otrivine

Original post by MathsNerd1

2/3 marks, last point should have been that the enthalpy change of hydrognation of benzene is less exothermic than that of Kekule. My turn

Reply 415

MathsNerd1

Original post by otrivine

2/3 marks, last point should have been that the enthalpy change of hydrognation of benzene is less exothermic than that of Kekule. My turn

Oh okay, my bad, I'll remember to write that aswell although it seems like quite a lot to write for 3 marks.

For you, when would you use D2O and what is it used to identify? (2)

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Reply 416

otrivine

Original post by MathsNerd1

D2O is a deuterating solvent and is an isotope of hydrogen. It is used in NMR spectrums. You would use D2O if there are any OH and NH groups present and it is used so that it does not show up in the NMR spectrum of both carbon and proton as the OH and NH have no splitting patterns and have a wide range and broad range of different chemical shifts depending on concentration and solvent used of D2O. It results in proton exchange in which the hydrogen gets replaced in OH and NH.