[ummm]

(Original post by lydia12)
on the sample paper the question was:

The following liquids have a similar number of electrons per molecule. Suggest which is likely to have the highest boiling point?
A) CH3CH2CH2CH2CH3
B) (CH3)3C0H
C) CH3CH2CH(OH)CH3
D) CH3CH2CH2CH2OH

and the answer was B, but i thought branching decreased boiling point so i thought it was d (as i know OH groups increase boiling point) hellppp

I probably would have put D as well... By the way, I wouldn't trust the mark schemes for the sample papers... for the Edexcel biology unit 1 one, there were definitely mistakes in it...

[avipsita]

(Original post by Clare~Bear)
Thinking about it, that should be the answer. cos the end answer is +/- you only use 0..04, not 0.08. But the person who asked it said the answer should be 0.8

(Original post by ummm)
Yeah, that's right! How did you get it though? I kept ending up with + or - 0.8 too...

thats good ... the thing is there are 2 10.0cm3 .. one for the acid and on for alkali .. so the total is 20cm3.. we need to measure each one of them .. so we use 2 pipettes and each one has an error of 0.04.. so then the percentage error is

(0.04*2/20 )*100 % =0.4%

[ummm]

(Original post by avipsita)
thats good ... the thing is there are 2 10.0cm3 .. one for the acid and on for alkali .. so the total is 20cm3.. we need to measure each one of them .. so we use 2 pipettes and each one has an error of 0.04.. so then the percentage error is

(0.04*2/20 )*100 % =0.4%

I always thought you had to calculate the percentage error for each piece of equipment though, and then add them to find the total percentage error.

so basically (0.04/10) * 100 + (0.04/10) * 100 = 0.8%

Can't believe CGP lied to me

[UserInvalid]

(Original post by ummm)
I've done all of them. Sometimes they're alright... I just did the June 2011 and only lost 3 marks, but then some of them have tricky organic stuff in it, and I always seem to draw the equipment out wrong....

As long as you know your stuff well it should be alright!

what are the most common questions asked in the papers?

[ummm]

(Original post by UserInvalid)
what are the most common questions asked in the papers?

There's usually always an extended iodine-sodium thiosulphate calculation question, and there's often quite a lot of recall... like "what colour would this turn... blah blah blah", umm, quite a lot of intermolecular forces stuff in the MCQ, and usually a bond angle question somewhere. They usually focus on halogenoalkanes or alcohols imo, and then you've got the 'green chemistry' ish section C, which is usually pretty straightforward...

[itsmehello]

I hate sodium Iodine thiosulphate calculation questions

[avipsita]

(Original post by Killer_94)
I absolutely HATE redox reactions... I'm so scared for this exam

they are actually really easy .. i am struggling on chapter 2.2 and 2.3

[Assassin94]

my chemistry teacher told us that this unit 2 is more just learning it off, than actually understanding it. i know there's a certain amount that has to be understood to get top marks, but do you agree that it's mostly just learning what the books say? i'm not so sure?

[Assassin94]

is section C usually on green chemistry? like would that mostly be just revise straight from the books?

[Dovah13]

(Original post by Assassin94)
is section C usually on green chemistry? like would that mostly be just revise straight from the books?

yeah pretty much all the time its about green chemistry.. i hate chemistry, thought it would be more fun but im just going to drop it even if i get an A.

[Blob2491]

(Original post by Dovah13)
yeah pretty much all the time its about green chemistry.. i hate chemistry, thought it would be more fun but im just going to drop it even if i get an A.

This is madness

[AmrinderRai]

Is it just me? Or is unit 1 to unit 2 a bigger jump than gcse to as level :/

[Dovah13]

(Original post by AmrinderRai)
Is it just me? Or is unit 1 to unit 2 a bigger jump than gcse to as level :/

I agree.

[LNH10]

is there likely to be many definitions in this unit, or not?

[Arusa01]

(Original post by LNH10)
is there likely to be many definitions in this unit, or not?

Not really, maybe a few. Mostly applied chemistry

[d_94]

God, this is hard! :'(

[Otlichno]

I'm repeating this Unit because I got a C in January. But since I have Unit 6 tomorrow I only really have a day and a half to revise. God help me.

[ummm]

Yay, with biology over I can finally focus on this! I actually quite like this unit now! Thought it was horrendously difficult the first time I went through it, but it's not tooo bad.

The gap between unit 1 and 2 is massive though in terms of difficulty of the theory.
Way bigger than the gap between GCSE and unit 1!

[Arusa01]

(Original post by Otlichno)
I'm repeating this Unit because I got a C in January. But since I have Unit 6 tomorrow I only really have a day and a half to revise. God help me.

Unit6? I'm resitting too, hopefully this time round it'll be better.

[Otlichno]

(Original post by Arusa01)
Unit6? I'm resitting too, hopefully this time round it'll be better.

I'm doing it with the A-levels.