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OCR Chemistry F322~ 4th June 2013~ AS Chemistry

Reply 380

Jimmy20002012

OP

4

Could anyone summarise the types Isomers and how to deduce how many isomers can be drawn?

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Reply 381

needtosucceed=)

10

Original post by Jimmy20002012

Could anyone summarise the types Isomers and how to deduce how many isomers can be drawn?

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structural - same molecular formula different structural arrangement
stereoisomerism - same structural formula different arrangement in space
e/z - type of stereoisomeism 2 different groups attached to each carbon atom
cis-trans - type of e/z in which 2 of the groups are hydrogen and the other 2 are non-hydrogen.
e/z and cis trans occur due to restricted rotation around the carbon carbon double bond

there really is no way to work out how many isomers there are, you just have to draw them all out. if theres a question asking u to number how many there are then just guess, if its got a really long molecular formula its gonna take u way too long to figure it out and its only 1 mark. guessing somewhere between 5-10 is quite safe.

Reply 382

wndms

1

In my book it says "methanol can be produced from biomass". Is it only methanol that is made from biomass? How about other kinds of alcohol?

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Reply 383

That_Clever_Guy

2

Original post by wndms

In my book it says "methanol can be produced from biomass". Is it only methanol that is made from biomass? How about other kinds of alcohol?

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Biomass releases methane which then can be reacted with water vapour (steam) and therefore produce methanol :smile:

I think that's correct lol

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Reply 384

ladybug.hugsxoxo

Hi guys as silly as this is i haven't started revision for f322 (been ill and other exams ) and I'm being overwhelmed by the content as I presently try and make a timetable for it ? Anytips on how to cram or any predictions on what will come up ? Please and thankyou xx

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Reply 385

MichaelP96

Original post by ladybug.hugsxoxo

Hi guys as silly as this is i haven't started revision for f322 (been ill and other exams ) and I'm being overwhelmed by the content as I presently try and make a timetable for it ? Anytips on how to cram or any predictions on what will come up ? Please and thankyou xx
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Don't worry about it, there's many over people in the same position
I haven't started yet either due to having 3 retakes!

Which bits are you finding hard? I think it's best if you cover the first part (Hydrocarbons) because in my opinion it's the longest part!

Alcohols and Analysis needs to be your 2nd Priority because alcohols can be pretty tricky, the mechanisms need to be learnt also because they hold a lot of marks in the exam. In the Jan 2013 paper there was a 14 mark question on two reaction mechanisms! Resources can be easily covered in a day or two.

Reply 386

Sid101

Oh my God I do not understand Mass Spec or IR Spec at all! How do I even go about approaching one of those long 10 mark questions?! Someone please help? :confused:

Reply 387

furryface12

21

Original post by Sid101

Oh my God I do not understand Mass Spec or IR Spec at all! How do I even go about approaching one of those long 10 mark questions?! Someone please help? :confused:

I feel exactly the same if that's any consolation, them and reaction mechanisms I can't get my head round at all! Unfortunately they seem to be the big mark questions... Sorry I can't help though!

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Reply 388

Sara_A

This is my only exam left and i have about 12 days to revise for it

Reply 389

Geronimo!

7

I have to do well in this unit, it'll really boost my grade and make A2 easier hopefully
I also have ****ty physics and after Mondays exam I've lost hope on physics in general
:frown:

(edited 10 years ago)

Reply 390

ellemcjelly

Original post by Geronimo!

I have to do well in this unit, it'll really boost my grade and make A2 easier hopefully
I also have ****ty physics and after Mondays exam I've lost hope on physics in general
:frown:

i know i have bio too its a nightmare. if we lost like 5/6 marks in the first chem, what do you think we need in this one to get an A?

Reply 391

ellemcjelly

Original post by Sara_A

This is my only exam left and i have about 12 days to revise for it

lucky!

Reply 392

Blashnet

8

Original post by ellemcjelly

i know i have bio too its a nightmare. if we lost like 5/6 marks in the first chem, what do you think we need in this one to get an A?

you'd need about 85, based on past grade boundaries.

Reply 393

ImAz

6

Is this paper out of 100?

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Reply 394

DefaultSkin

8

Original post by Blashnet

you'd need about 85, based on past grade boundaries.

I had a look at the paper in class and it looks like I've got about 43marks but in the practical I've got 39/40. So my teacher said I need about 85+ to get an A if that helps. :smile:

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Reply 395

DefaultSkin

8

Original post by ImAz

Is this paper out of 100?

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Yeah it is

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