AQA CHEM1: 15th May 2012

Original post by lfc4lyf

oh god i think ive revised enough but if there is alot of hsw then how we meant
to revise it as the textbook doesnt have that much hsw

well i tend to at the side of the page bulletpoint what topic its related to, and what could apply to the situation, have a look online and just do as many practice papers as possible.

Reply 142

Hello everyone.

I'll be doing this exam again along with CHEM2. I am becoming pretty much an expert now so if anyone wants to do a little study-buddy exchange, I'll be happy to be of help (or vice-versa). :smile:

Reply 143

Jack_Smith

8

Original post by 4MANU4EVER4

HELP with Jan 11 Chem 1 question

2) c) (ii),
3) a) (iii), (iv) and (v)

really stuck :confused:

pls help

thanks

Basically of 3aiii
we worked out how many moles reacted with HCL, but if you see the volum of the two one i 250 and the other is 25. Hence we need to multiply the answer we got for 3aii by 10.

iv. You do: moles = mass/Mr
Mr = Mass /moles we got the moles and we know the mass
Mr= 138.2

v.We know the Ar of C and o3 (12 +16*3) and then we divide by 2 to Get as they gave it as M2

Hope you get it!

Reply 144

Original post by HadrianH

Hello everyone.

I'll be doing this exam again along with CHEM2. I am becoming pretty much an expert now so if anyone wants to do a little study-buddy exchange, I'll be happy to be of help (or vice-versa). :smile:

ahh fire some questions for me please :smile:

Reply 145

SHAH :)

do we need to know about isomers for this unit or is that unit2?

Reply 146

Original post by SHAH :)

do we need to know about isomers for this unit or is that unit2?

Yes we do. Mainly positional isomerism (carbon chain arranged differently).

Reply 147

Original post by AishaTara

ahh fire some questions for me please :smile:

Hi Aisha,

Just quick revision from Jan '12 paper --

What are the conditions needed for thermal cracking to occur?

How is ice structured? Explain in terms of bonding. Give general properties.

Reply 148

4319

Does anyone have the JAN 2012 paper. Im goin to do it as practose before tommrows exam

Reply 149

iamthebest

Original post by 4319

Does anyone have the JAN 2012 paper. Im goin to do it as practose before tommrows exam

there should be another thread, check for threads with attachments

Reply 150

iamthebest

Original post by SHAH :)

do we need to know about isomers for this unit or is that unit2?

learn: positional, functional and chain

E/Z is unit 2

Reply 151

Original post by HadrianH

Hi Aisha,

Just quick revision from Jan '12 paper --

What are the conditions needed for thermal cracking to occur?

How is ice structured? Explain in terms of bonding. Give general properties.

thermal cracking
high temp 700-1200K
high pressure usually around 7000KPa
not sure what else

ice is denser than water, as water molcules are spaced further apart
hydrogen bonds are present

Reply 152

4319

I cant find the jan 12 unit 1 paper. Can someone upload it plz

Reply 153

Original post by AishaTara

thermal cracking
high temp 700-1200K
high pressure usually around 7000KPa
not sure what else

ice is denser than water, as water molcules are spaced further apart
hydrogen bonds are present

For thermal cracking it is >=10 atm

Ice is LESS dense than water! Remember density = mass/volume -- if the water molecules are spread further apart then volume would be greater; as density and volume are inversely proportional, it would mean that density is less.

Good job otherwise. Your turn to ask questions now. :smile:

Reply 154

4MANU4EVER4

4

Original post by Jack_Smith

Basically of 3aiii
we worked out how many moles reacted with HCL, but if you see the volum of the two one i 250 and the other is 25. Hence we need to multiply the answer we got for 3aii by 10.

iv. You do: moles = mass/Mr
Mr = Mass /moles we got the moles and we know the mass
Mr= 138.2

v.We know the Ar of C and o3 (12 +16*3) and then we divide by 2 to Get as they gave it as M2

Hope you get it!

thank you i finally get it

Reply 155