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OCR Salters Chemistry B F332 Advance Notice May 2011 Polymers on the move

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What is meant by Crystalline?

Crystalline
Regions have a high degree of order/ regular/ chains more aligned (1);
the chains move over each other less easily (1);
because there are stronger imf (1); (IGNORE “more imf”)
due to molecules being closer together (1)

I don't think the idea of crystalline is in the spec anymore.

Reply 101

Toshiya

Original post by Bi0logical

Thanks!

But, a couple of weeks back I was doing an old spec past paper that had a question on crystalline polymers on it - I'd never heard the term crystalline, so I asked my teacher, and she said it was old spec and we didn't need to know it any more...

Can anyone confirm if it's still in the spec? I can't find it in the revision guider either!

Reply 102

nutbeam

Original post by Toshiya

Im pretty sure it isnt, it's not in any of the textbooks...

Reply 103

gozatron

I remember seeing crystalline and amorphous in the chemical ideas somewhere? Maybe not for F332..

Reply 104

Hudzy

Original post by gozatron

I remember seeing crystalline and amorphous in the chemical ideas somewhere? Maybe not for F332..

I think it's been moved to A2.

Reply 105

lily92

Original post by Hudzy

Yeah I took it off the internet without realising it had an extra carbon. I posted an updated version but you probably missed it. I'll change the version on the old post to stop confusing people :tongue:

Here is the update anyway.

You are my hero! - For the revision polymer thing :L

Reply 106

lily92

Original post by gozatron

Anyone got a handy list of the reaction reagents and conditions we need to know?

The Jan 11 paper and Mark scheme would be pretty handy aswell :biggrin:

Thanks

Did you find a list of the reagents and conditions?

Reply 107

Toshiya

Anyone know exactly what points the mark scheme are looking for when they ask how ID-ID, PD-PD and H bonds are formed?
I always trip up on the wording with those questions!

Reply 108

icedragon

Original post by Toshiya

Anyone know exactly what points the mark scheme are looking for when they ask how ID-ID, PD-PD and H bonds are formed?
I always trip up on the wording with those questions!

ID-ID

Electron movement causes an uneven distribution of charge. This induces a dipole in a neighbouring molecule, followed by attraction.

PD-PD

Simply one atom more electronegative than the other (explain that method if necessary) in a covalent bond, so PD-PD formed between different atoms of each molecule.

Hydrogen bond

Slightly positive H atom is attracted to the lone pair on an oxygen atom so H bond formed.

Key marking points underlined.

(edited 12 years ago)

Reply 109

Fosteeer

the person that did the polymers on the move sheet is a GENIUS! MUCH LOVE FOR YOU!!

Reply 110

Toshiya

Original post by icedragon

) formed between molecules.

Hydrogen bond

Slightly positive H atom is attracted to the lone pair on an oxygen atom so H bond formed.

Key marking points underlined.

Thanks! That's exactly what I wanted, whenever I answer a question like that I just waffle and still only manage to put in half of the points. :biggrin:

Reply 111

Glennith

Original post by gozatron

Anyone got a handy list of the reaction reagents and conditions we need to know?

The Jan 11 paper and Mark scheme would be pretty handy aswell :biggrin:

Thanks

Try the spec, there's some, in that...

I bloody hate those reaction conditions. :rant:

EDIT: page 21.

(edited 12 years ago)

Reply 112

icedragon

Original post by Toshiya

Thanks! That's exactly what I wanted, whenever I answer a question like that I just waffle and still only manage to put in half of the points. :biggrin:

No problem. Just to note, it is PD-PD apparantly (I guess because its between 2 molecules and not intramolecular). Also remember to spell ID-ID and PD-PD out fully and correctly especially if there are any QWC marks.

Reply 113

Toshiya

Original post by icedragon

Cheers.
And yeah, I know now to write them out fully... found out the hard way when I lost marks on a couple of mocks we did in class because I just put 'ID-ID'
Turns out if they ask for QWC marks on a question like that you often get them for spelling instantaneous and induced correctly.

Reply 114

icedragon

Original post by Toshiya

Yep, or for linking your ideas together. So for example when describing how CO2 warms the Earth, you would get a QWC for saying "UV from the sun is absorbed by the Earth which heats the Earth and in turn it emits IR". Connection of ideas will get you that mark really.

Reply 115

Tobywonderboy

Just wondering if anyone has any sort of notes on the entire specification, or sheets similar....
I could do with some cramming material to read through tomorrow :smile:

Reply 116

icedragon

Worth knowing about free radical polymerisation (free radical addition):

The chain is initiated by radicals produced by the reaction between the alkene and an oxygen initiator. When these radicals meet a longer free radical is formed:

This chain continues:

Until termination where two of the radicals meet making a final molecule:

It's important to note that the chain termination is random, because 2 radicals could meet at any time (between long chains or short chains), so the polymer itself will be made up of chains of all different lengths.

(edited 12 years ago)

Reply 117

Toshiya

icedragon... I've never heard of free radical polymerisation.
I'll be having words with my chemistry teachers when we go back if that comes up tomorrow and I can't do it >_>

Reply 118

bugsymalone

Original post by icedragon

This chain continues:

Until termination where two of the radicals meet making a final molecule:

icedragon you really are a respected and adored member, if it wasn't for you and hudsy i wouldn't have had a shot at this exam

THANKS :biggrin:

Reply 119

icedragon

Original post by Toshiya

icedragon... I've never heard of free radical polymerisation.
I'll be having words with my chemistry teachers when we go back if that comes up tomorrow and I can't do it >_>

It's basically the actual mechanism for addition polymerisation (it's how they add together). I think it's in the syllabus as it's in some of my guides but if it isn't, it could quite possibly be useful for the advanced notice question. I quote from the advanced notice:

"These are polymerised by a free radicalinitiated polyaddition." - from the Bonding polyalkenes section.

So they could very possibly ask you about the mechanism I explained.

Original post by bugsymalone