Chemistry paper 3 doubts here!!!

[shan5674]

Heyy i have alot of doubts in chem paper 3 so i thought ill start this new thread...please ppl help mee

http://www.xtremepapers.me/CIE/Cambridg ... _qp_31.pdf
Q4, c(ii) how do i draw that? :S

 

[xIshtar]

Two CH3 bonded together, with one Sulphur bonded to them all, it is a covalent compounds, so electrons are shared.

 

[skinnyboyfat]

drawing it would b better idea...

 

[shan5674]

Two CH3 bonded together, with one Sulphur bonded to them all, it is a covalent compounds, so electrons are shared.

Could you draw it for me pleaseeee?

 

[HorsePower]

it'll be like this

 

[shan5674]

it'll be like this

Thank youu soo much :Yahoo!:

 

[shan5674]

http://www.xtremepapers.me/CIE/Cambridg ... 9_qp_3.pdf

Can someone solve q5 part b for me pleaseee, its sooo confusing :S

 

[skinnyboyfat]

^^i couldnt solve it either...have a look at this
on second page 1st post...see if it helps...

 

[Outofideaz]

wats the repeating unit for proteins ... wat do i write if they aske the structure of proteins?? i looked at the syllabus its there but how do i write it in brackets with the "n" ???

 

[shan5674]

^^i couldnt solve it either...have a look at this
on second page 1st post...see if it helps...

Hey thanks alot i kinda got it

 

[shan5674]

wats the repeating unit for proteins ... wat do i write if they aske the structure of proteins?? i looked at the syllabus its there but how do i write it in brackets with the "n" ???

I dont think u can do it with the "n" and brackets :no: i just know the NHCO bond for protein

 

[shan5674]

http://www.xtremepapers.me/CIE/Cambridg ... 7_qp_3.pdf

Q3 helpp i dont get how im suppose to know the reagent and stuff :/

 

[shan5674]

http://www.xtremepapers.me/CIE/Cambridg ... 4_qp_3.pdf

look at qs4..part b..ii..
i dont understand the answer. what is the theory behind it etc. plz explain

The link u gave does not work :S

 

[breakheart]

http://www.xtremepapers.me/CIE/Cambridg ... 4_qp_3.pdf
look at qs4..part b..ii..
i dont understand the answer. what is the theory behind it etc. plz explain

 

[JmCullen]

http://www.xtremepapers.me/CIE/Cambridge%20IGCSE/0620%20-%20Chemistry/0620_s07_qp_3.pdf

Q3 helpp i dont get how im suppose to know the reagent and stuff :/

(i) reagent is sulphuric acid. cuz u need a sulphate.

(ii) HCl

(iii) iodide

 

[shan5674]

http://www.xtremepapers.me/CIE/Cambridge%20IGCSE/0620%20-%20Chemistry/0620_s04_qp_3.pdf
look at qs4..part b..ii..
i dont understand the answer. what is the theory behind it etc. plz explain

i dont get it either, im sorry :sorry:

 

[shan5674]

http://www.xtremepapers.me/CIE/Cambridge%20IGCSE/0620%20-%20Chemistry/0620_s07_qp_3.pdf

Q3 helpp i dont get how im suppose to know the reagent and stuff :/

(i) reagent is sulphuric acid. cuz u need a sulphate.

(ii) HCl

(iii) iodide

But can u explain how you came up with those answers :/ i dont get how im suppose to figure it out

 

[Parfals]

howz all u r preparation check this might be useful viewtopic.php?f=24&t=9387

 

[shan5674]

http://www.xtremepapers.me/CIE/Cambridg ... 4_qp_3.pdf

q4 (iii)

 

[xIshtar]

http://www.xtremepapers.me/CIE/Cambridge%20IGCSE/0620%20-%20Chemistry/0620_s04_qp_3.pdf

q4 (iii)

4 a(iii) or b(iii)

I'll explain both anyway..

For a(iii) : Ag+ + Cl- -> AgCl

For b(iii): It would reach a maximum, then fall back to zero. This is because when there is aluminium and NaOh, a precipitate forms which is soluble in excess

Hope I helped guys