IGCSE/GCSE/O & A Level/IB/University Student Forum

Qualification => Subject Doubts => GCE AS & A2 Level => Sciences => Topic started by: aldehyde1612 on May 26, 2010, 03:29:47 pm

Title: Help/advice CHEMISTRY. CIE...? :)
Post by: aldehyde1612 on May 26, 2010, 03:29:47 pm

So next is chemistry paper 2.
i get most of the organic part.. and the general chemistry.
but when it comes to inorganic i get stumped.

Can anyone tell me what i should be clear on??... because i generally understand it but when i did some 'inorganic' questions in pastpapers .. i find myself plainly doing guess work.. :-\
so if anyone has any tips/study help for paper 2... or just anything chemistry. POST!!

;D

Title: Re: Help/advice CHEMISTRY. CIE...? :)
Post by: nid404 on May 26, 2010, 03:34:05 pm

PAST PAPERS

Post questions you have problems with, I'll do my best to help you out.

And cause you have problems with inorganic chem...and if you wish to revise the chpts again, go through http://www.knockhardy.org.uk/sci.htm

Ask for help if needed  :)

Title: Re: Help/advice CHEMISTRY. CIE...? :)
Post by: aldehyde1612 on May 27, 2010, 10:15:50 am

Thanks..  ;D that websites pretty awesome.

just wondering... what years should i do the pastpapers from. Ive started from 2006. ??

Title: Re: Help/advice CHEMISTRY. CIE...? :)
Post by: nid404 on May 27, 2010, 10:23:53 am

Yeah good enough. If you get time , do the older ones too. As many as you can  :)

Title: Re: Help/advice CHEMISTRY. CIE...? :)
Post by: aldehyde1612 on May 29, 2010, 01:23:27 pm

can u please help me with ... oct 2009 paper22... question 3c.???

 ???

Title: Re: Help/advice CHEMISTRY. CIE...? :)
Post by: nid404 on May 29, 2010, 02:45:43 pm

here u go
the eqn is C4H9OH+ HBr---->C4H9Br+ H2O

ratio is 1:1

15.4g of butanol = 15.4/ 74 = 0.208

so theoretically there should be 0.208 moles of bromobutane produced= 28.51 g

but only 22.5g are produced
so yield is 22.5/28.51 X 100= 78.9%

Title: Re: Help/advice CHEMISTRY. CIE...? :)
Post by: ruby92 on May 29, 2010, 09:38:38 pm

when drawing a skeletal formula for the fuctional group c is emitted in say CHO?

Title: Re: Help/advice CHEMISTRY. CIE...? :)
Post by: nid404 on May 30, 2010, 05:29:31 am

Carbon atoms are the joints so you don't name them.

You cant have a skeletal formula for such a functional group