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EDEXCEL CHEMISTRY Module 4

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Reply 60

satpanth

rfrd you are right it was 0.01 definitly cause my teacher went through that question. I got that too yh

Reply 61

rfrd

does anyone remember what the ka value was in the buffer solution question?

Reply 62

ReasonToBelieve

rosemkate

i also thought that it was 80% to get an A. Does anyone know for sure what the grade boundaries are?

They vary slightly from year to year. Some years an A is 56 others 54. This means that 56 = 72/90.

Proof..http://www.chemistry.thornburycottage.com/MS3.htm
Check out "Marks and then go into examination report. I think our paper is the **45 one.

And yes. -186kjmol-1. Didn't mean -178 or whatever

Reply 63

ReasonToBelieve

FAT-ema

I think the secondary alcohol is oxidised to give a ketone but has no reaction for the
ester...that's why it reacts to give CHI3......am I the only one to have put that answer?? :s-smilie:

I put no reaction for ester and a ketone for the second one too. But according to my teacher the first one reacts and the second one does not. Stoopid question really. Any other type and i would have got it. Grr.
3rd one gave carboxylic acid. i think. i cant really remember. deffo reacted. 2 marks gone.

Reply 64

rfrd

i thoguht only the bottom reacted because it was tollens reagent?1
lost a lot of marks

Reply 65

rohitkhannak

My teacher said that only the aldehyde reacted. I told her that the first compound also had a C=O bond (she hasn't seen the paper) but she still says that only the aldehyde would react ... Even ketone has a C=O group.

Reply 66

rfrd

yeh i thought it would only be the bottom because even ifthe others had a c=o bond they wouldnt be able to oxidise. tollens and fehlings only oxidise aldehydes. altleast most of these were one markers ...

Reply 67

sweethunni01

what did everyone get for the monomers/polyamide question (the last question)

was it: ClOC(CH2)6COCl and NH2(CH2)4NH2

Reply 68

rfrd

thats what i got for it

me too

Ferchichi

URGHHHHHHHH
THAT WAS A ****.

Seriously!

I was hoping so much that nothing with nitrogen would come up. URGHHHHHHHHH AND IT WAS ALL ABOUT FREAKING NITRILES AND AMINOS. AGHHHH.

What was the cooling rapidly question about. :s-smilie:

I didnt have a clue, I just put so that the gases dont escape and accurate measurements of volume can be recorded to calculate accurate concentrations. But that was prob wrong, what did everyone else put?

I put because the forward reaction is endothermic, if you cool it, you're keeping the mixture at its equilibrium making for accurate calculations at that equilibrium

Reply 71

Evizu

I heard it was an alright paper really, I dont do chemistry but some friends of mine said it went good for them, from your commends im confused however i wish you all the best hehe

Vech

Reply 72

jammie08

jashan

I put because the forward reaction is endothermic, if you cool it, you're keeping the mixture at its equilibrium making for accurate calculations at that equilibrium