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Edexcel Chemistry A2 Unit 5 ~ Wednesday 19th June 2013 (Now Closed)

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Wow :/

I don't see how to approach the question for i) ... the temperature can't be above 10 degrees Celsius ? and cooled sodium nitrate may be used to maintain a temperature below 10 ?

Erm I am going to make an attempt on this and say that... if it is primary... there would be no extra alkyl groups to push electrons towards the nitrogen to make it less delta positive... because it's so delta positive it is a very powerful electrophile...

Do you have the answers ? :smile:

It's one of those textbooks where the answers are safeguarded.

Reply 721

posthumus

Original post by YAH

guys, how to reduce 4-nitrophenol to 4-aminophenol???

Where'd you get that from ? Can this come up in our exam :redface:

Well anyway, I hope this helps...

Reply 722

AtomicMan

Original post by YAH

guys, how to reduce 4-nitrophenol to 4-aminophenol???

I thought youd add conc HCl, tin and heat under felux? :s-smilie:

Anyway, is anybody else going over units 1,2 and 4?

Reply 723

posthumus

Original post by AtomicMan

I thought youd add conc HCl, tin and heat under felux? :s-smilie:

Anyway, is anybody else going over units 1,2 and 4?

Yup, I'm retaking all those... so I'm going through everything :smile:

Reply 724

AtomicMan

Original post by posthumus

Yup, I'm retaking all those... so I'm going through everything :smile:

Wow, good luck! Im going over them to try and recap all the organic because unit 5 seems to bring it all together :s-smilie:

How are you finding organic?

Reply 725

posthumus

Original post by AtomicMan

Wow, good luck! Im going over them to try and recap all the organic because unit 5 seems to bring it all together :s-smilie:

How are you finding organic?

Thanks, I will most definitely need it :redface:

I'm going over organic unit 5 today in fact, the george facer book which I am using does seem to sum up pretty much all of unit 4 organic chemistry & some unit 2 in my opinion :smile:

Organic seems okay, I usually hate it... but it's a lot better comapred to the non-organic chemistry :tongue:

What about yourself ?

Reply 726

AtomicMan

Original post by posthumus

Thanks, I will most definitely need it :redface:

I'm going over organic unit 5 today in fact, the george facer book which I am using does seem to sum up pretty much all of unit 4 organic chemistry & some unit 2 in my opinion :smile:

Organic seems okay, I usually hate it... but it's a lot better comapred to the non-organic chemistry :tongue:

What about yourself ?

Im finding organic chemistry a nightmare :lol:

Get reactions and reagents constantly mixed up. Then when I come back to review a topic, I forget everything :/

Reply 727

posthumus

Original post by AtomicMan

Im finding organic chemistry a nightmare :lol:

Get reactions and reagents constantly mixed up. Then when I come back to review a topic, I forget everything :/

I always forget it too :frown:

But I usually end up memorizing everything pretty well a couple of days before the exam! :tongue:

But hopefully my retakes would help me be more organised when going through pretty much the entire A level syllabus :smile:

Reply 728

jethacan

Original post by jojo1995

thank you

but as posthumus said there is an extra ch3 on the phenyl ethanol that needs to be removed

Original post by posthumus

Erm I believe an extra carbon is needed and the formula is C6H5COOH

I was thinking maybe CN- ions replacing the OH- to form H20 (or KOH for that matter)

using Unit 4 nitrile synthesis knowledge we can hydrolyze the C6H5CN as so:

C6H5CN + 2H20 + H+ ------> CH6H5COOH + NH4+

What do you guys think ?? :smile:

Oh yeah you're right, hmmm that seems really complicated then...

Edit: actually, just researched it and apparently KMnO4 will do it in one step :smile:

(edited 11 years ago)

Reply 729

jethacan

do we need to know the experiment to measure how much an amino acid rotates polarised light? I don't really understand it :s-smilie:

Reply 730

jojo1995

Original post by jethacan

Oh yeah you're right, hmmm that seems really complicated then...

Edit: actually, just researched it and apparently KMnO4 will do it in one step :smile:

Do you know what the equation would be ? ..., thank you so much :smile:

bah nvm

Original post by jethacan

Oh yeah you're right, hmmm that seems really complicated then...

Edit: actually, just researched it and apparently KMnO4 will do it in one step :smile:

I'm really not too sure about it...

Have you ever seen CN- replace an alcohol group ? If so do you know the conditions.

I just thought since the pi system of the benzene ring takes in the the long pair of oxygen's electrons the delta H+ would attract the CN-

but I'm not sure if what I am thinking is right :frown:

EDIT: Just saw the edit :smile:

I don't know how the KMnO4 would work... well where would the carbon come from ? :confused:

KMnO4 definitely works with aliphatic alcohols in the presence of H2SO4 to form Carboxylic group though.

(edited 11 years ago)

Reply 733

Weaselmoose

Original post by posthumus

I haven't seen the spec but the reactions I see in the George Facer book:

Reaction with bromine
Nitration
Reaction with diazononium ions
Reaction with water
Reaction with sodium hydroxide
Reaction with sodium
Reaction with sodium hydrogen carbonate
Reaction with acid chlorides

That's a fair few but I guess some of those are the same with alcohols and are from previous units :smile:

So the only new thing you haven't mentioned and I think we need to know is the reaction with diazonium ions

Yeah the spec only explicitly mentions the bromination and nitration and then the diazotization for making of dyes, but I guess the others are inferred like you said because we technically should know it from the other units :smile:

Reply 734

senz72

This may be a stupid question but what general name is given to polymers like neoprene and natural rubbers?

Reply 735

jethacan

Original post by posthumus

EDIT: Just saw the edit :smile:

I don't know how the KMnO4 would work... well where would the carbon come from ? :confused:

KMnO4 definitely works with aliphatic alcohols in the presence of H2SO4 to form Carboxylic group though.

Original post by jojo1995

Do you know what the equation would be ? ..., thank you so much :smile:

I haven't heard of the HCN replacing the -OH group, I've only heard of the addition of HCN on aldehydes and ketones, I don't know if you're thinking of that?

From phenylethanol to benzoic acid you're taking away a carbon, phenylethanol is C6H5CH2CH2OH and benzoic acid is C6H5COOH. I don't have an equation for it unfortunately jo, both look at this website though it's really helpful :smile:

http://www.masterorganicchemistry.com/reaction-guide/oxidation-of-aromatic-alkanes-with-kmno4-to-give-carboxylic-acids/

Reply 736

posthumus