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

Heya, could someone please give me mark scheme definitions of a ...
nucleophile and an electrophile please

Reply 83

Original post by qwerty123qwertyu

For oxidising a primary alcohol to an aledehyde, what are the reagents and conditions???

potassium dichromate, sulfuric acid and is it heat or distil???

some papers allow heat but some dont

Acidified Potassium Dichromate, Heat and distill as product forms.

Reply 84

Original post by Cleoleo

Heya, could someone please give me mark scheme definitions of a ...
nucleophile and an electrophile please

Nucleophile is molecule or negatively charged ion with a lone pair of electrons that can be donated to a slightly positive charged carbon atom to form a covalent bond.

Reply 85

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

Here's the Jan 11 stuff for you!

Advance Notice: http://www.mediafire.com/?0pk0cr3uc1x9oyi
Paper: http://www.mediafire.com/?qb1mp9ptswq9qli
Mark scheme: http://www.mediafire.com/?t332tw0pn2bcgc4

I haven't done much in the way of revision for the advance notice... I'm gonna go over that tonight and glance over the stuff again in the morning.
I'm currently getting mid-high 70s in practice papers... sure it's a low A, but an A's an A, right?

Reply 86

AdamBeee

has anyone get any ideas what the main questions in the rest of the paper may be aimed at?

Reply 87

bertiejess

Original post by polkadotty

can someone please help me...

Explain and describe, in terms of intermolecular bonding, the difference in properties between thermoplastics and thermosets?

I think that this would just mean thermosets have extensive crosslinks, thermoplastics don't have crosslinks, but i'm not 100% sure :s-smilie:

Reply 88

The atmosphere is the worst module ever.

Reply 89

Hudzy

8

Original post by gozatron

The atmosphere is the worst module ever.

Wouldn't mind either the 6 mark question on CFCs causing ozone depletion or the explanation of greenhouse effect. They come up so often that I've memorised the marking points. Both were on January 2010 so I hope they're coming around again.

Reply 90

Original post by Hudzy

Wouldn't mind either the 6 mark question on CFCs causing ozone depletion or the explanation of greenhouse effect. They come up so often that I've memorised the marking points. Both were on January 2010 so I hope they're coming around again.

That would be too nice of them, it'll probably be something similar to the Jan 11/Jun 10 one (?) which asked something like "How did the scientists measure Ozone loss" or even worse
If they ask something about climate models...

Reply 91

Original post by Hudzy

Wouldn't mind either the 6 mark question on CFCs causing ozone depletion or the explanation of greenhouse effect. They come up so often that I've memorised the marking points. Both were on January 2010 so I hope they're coming around again.

Ooh yeah, I wouldn't mind those either...
Looking over the January 2011 paper, the stuff I don't think is likely to come up is explaining how ID-ID bonds or H bonds form... there was a huge 7-marker on that and solubility of polymers.
There was a massive question on ozone in the troposphere as well, so I'm hoping that doesn't come up, since I always get my wording muddled trying to explain that!

I hope I do alright on the advance notice stuff, looking at past papers I seem to trip up mainly on the questions to do with advance notice... that's maybe because on all the past papers I've done I've looked at the advance notice to go with it as I'm doing the questions... at least I hope that's the reason!

Good luck everyone! :biggrin:

Reply 92

Original post by Toshiya

Ooh yeah, I wouldn't mind those either...
Looking over the January 2011 paper, the stuff I don't think is likely to come up is explaining how ID-ID bonds or H bonds form... there was a huge 7-marker on that and solubility of polymers.
There was a massive question on ozone in the troposphere as well, so I'm hoping that doesn't come up, since I always get my wording muddled trying to explain that!

I hope I do alright on the advance notice stuff, looking at past papers I seem to trip up mainly on the questions to do with advance notice... that's maybe because on all the past papers I've done I've looked at the advance notice to go with it as I'm doing the questions... at least I hope that's the reason!

Good luck everyone! :biggrin:

Luckily enough I don't think the advanced notice is that critical, just seems like it's stimulus material for them to ask storyline questions. Which is worrying because PR doesn't have much storylines!

Reply 93

Original post by gozatron

Luckily enough I don't think the advanced notice is that critical, just seems like it's stimulus material for them to ask storyline questions. Which is worrying because PR doesn't have much storylines!

I don't think it is either, I think it's quite a nice advanced notice for us actually, seeing some of the past ones this one seems nicer.
Since PR is the smallest chapter they're more limited with the stuff they can ask us... it's seeming fairly easy to predict the questions they can ask. Which is ok with me!

Reply 94

icedragon

Original post by bertiejess

I think that this would just mean thermosets have extensive crosslinks, thermoplastics don't have crosslinks, but i'm not 100% sure :s-smilie:

These are properties of them yes, but the definition is that thermoplastics can be deformed with heating, and thermosets cant.

Reply 95

icedragon

Original post by Toshiya

I don't think it is either, I think it's quite a nice advanced notice for us actually, seeing some of the past ones this one seems nicer.
Since PR is the smallest chapter they're more limited with the stuff they can ask us... it's seeming fairly easy to predict the questions they can ask. Which is ok with me!

What are your guesses for what they might ask us? And is it worth me reading the storylines for PR? I bought it but never read it all year! :colone:

Reply 96

Bi0logical

7

Catalyst notes:

A pair of reacting molecules must collide, with a combined energy which is greater than the activation enthalpy for the reaction, in order to make a successful collision.
Catalysts are used in order to overcome the activation energy barrier more easily. Catalysts are used in order to overcome the activation energy barrier more easily. Also successful collisions can take place at a lower energy - this is called lowering the activation energy barrier.

Catalysts provide an alternative pathway for the breaking and making of bonds. This alternative pathway has a lower activation enthalpy than an uncatalysed pathway.

Heterogeneous catalysts; the reactants and catalysts are in different physical states.
They provide a surface on which a reaction may take place; therefore lowering the energy needed for successful collision - this lowers the activation energy barrier.

Homogeneous catalysts; the reactants and catalysts are in the same physical state.

Reply 97