Chemistry: Post your doubts here!

[salvatore]

thanks
but can you tall me if diazotisation is nucleophilic substitution

Sorry.. I'm still doing AS.. that must be A2 right?

 

[megamind]

marking scheme says- explanation-
H Cl line at 36 has rel. abundance of 90 (1) read off from the graph,
38 30
These show Cl and Cl in ratio 3:1 (1) we get simplest ratio
[or use of 35 and 37]
Mean of the two isotopes 3 x 35 + 1 x 37 = 35.5 (1) exactly same as my working but whole fraction has been divided by 25(just simplification doent matter
4

 

[megamind]

you

Sorry.. I'm still doing AS.. that must be A2 right?

must be a geeenious in your AS

 

[salvatore]

you

must be a geeenious in your AS

Lol.. not really

 

[syed1995]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s11_ms_23.pdf check ans 3b the graph drawn is wrong isnt it. we have to draw sodium above phosphorus and sulfer?

Aye. Plus S would be a little higher than P.

 

[syed1995]

A star

should have been something like this

 

[abruzzi]

I have a doubt concerning polymers. When drawing structures of polymers with more than two carbon atoms, is it necessary to include only two carbon atoms in the main chain and the rest as side chain? Here's is an example:
http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_s03_qp_2.pdf
Question no. 5(a).. please check what the marking scheme has done.
Thanks

 

[syed1995]

I have a doubt concerning polymers. When drawing structures of polymers with more than two carbon atoms, is it necessary to include only two carbon atoms in the main chain and the rest as side chain? Here's is an example:
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s03_qp_2.pdf
Question no. 5(a).. please check what the marking scheme has done.
Thanks

No it's not necessary.

You can have polymer like this as well...

-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C- as well.. but that would get cluttery.. and won't even fit in the page.. hence why one would branch them..

-CH2-CH(C4H9)- CH2-CH(C4H9)- CH2-CH(C4H9)- something of that sort would be appropriate over here...

 

[abruzzi]

No it's not necessary.

You can have polymer like this as well...

-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C- as well.. but that would get cluttery.. and won't even fit in the page.. hence why one would branch them..

-CH2-CH(C4H9)- CH2-CH(C4H9)- CH2-CH(C4H9)- something of that sort would be appropriate over here...

Oh.. alright.. thanks

 

[ramnarace]

Can someone please do the graph 2(b) from may/june 2009 paper 5. Im not too certain on how to extrapolate the 2 lines.
Thank you very much

 

[Alice123]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s11_qp_21.pdf
in Q3d, Can ne1 specify which one's reaction 1??

 

[iKhaled]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s11_qp_21.pdf
in Q3d, Can ne1 specify which one's reaction 1??

reaction one is written "reaction 1" in bold..wakie wakie i think u didn't sleep much its from W -------> Z

 

[A star]

reaction one is written "reaction 1" in bold..wakie wakie i think u didn't sleep much its from W -------> Z

omg i didnt notice xD
nice one

 

[A star]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s11_qp_21.pdf
in Q3d, Can ne1 specify which one's reaction 1??

its a double displacement reaction name any soluble sulphate salt like Na2SO4

 

[iKhaled]

omg i didnt notice xD
nice one

hehe

 

[HorsePower]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w12_qp_43.pdf
Q4 b i)
can anyone tell me how to find D ?

 

[A*(a*)]

Can anyone help me with this? please? OCT/Nov 04 q13

 

[PANDA-]

Can anyone help me with this? please? OCT/Nov 04 q13

Is it A?

 

[PANDA-]

Is it A?

Oops, It's C, was my second choice. LOL
No idea why though..

 

[Alice123]

Can ne1 give an example of acylation in halogenoalkane formation?