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Qualification => Subject Doubts => IGCSE/ GCSE => Sciences => Topic started by: Numb on April 07, 2010, 11:25:40 am

Title: Chemistry
Post by: Numb on April 07, 2010, 11:25:40 am
Draw a possible structre of dibromobutane.

the mark scheme says any correct formula for a dibromo methane??????
Title: Re: Chemistry
Post by: Saladin on April 07, 2010, 12:21:24 pm
here u go
Title: Re: Chemistry
Post by: haris94 on April 07, 2010, 02:04:42 pm
2 POSSIBLE SOLUTIONS
1) u read it wrong
2) typing error in the mark scheme

if its dibromo methane, numb is correct
if its dibromo butane,
its C4H8Br2 (molecular formula)
Title: Re: Chemistry
Post by: Saladin on April 07, 2010, 03:37:44 pm
Quote from: haris94 on April 07, 2010, 02:04:42 pm
2 POSSIBLE SOLUTIONS
1) u read it wrong
2) typing error in the mark scheme

if its dibromo methane, numb is correct
if its dibromo butane,
its C4H8Br2 (molecular formula)

Sorry abt that, my head was messed up. LOL

Anyways the answer is attatched.

Its just that, the 2 in the di-bromo can be acheived from both ends. One is just the other turned 180o
Title: Re: Chemistry
Post by: haris94 on April 07, 2010, 04:11:45 pm
@ the ultimate dude :
u r right bout the answer but i think what numb is trying to say is that the question asks for dibromo butane while the mark scheme says "any correct formula for dibromo methane"
either that or numb typed it wrong over here
 
Title: Re: Chemistry
Post by: Saladin on April 07, 2010, 04:21:25 pm
Quote from: haris94 on April 07, 2010, 04:11:45 pm
@ the ultimate dude :
u r right bout the answer but i think what numb is trying to say is that the question asks for dibromo butane while the mark scheme says "any correct formula for dibromo methane"
either that or numb typed it wrong over here
 

LOL, then that is wrong. Because why would they want that. Anyways, the correct markscheme statement would be 'any structure of dibromobutane', which basically means that, any of the two. This is funny, because u will get some questions like these at a level as well, when it comes to reactions and breaking double bonds.
Title: Re: Chemistry
Post by: holtadit on April 07, 2010, 04:57:27 pm
@Dude


shouldnt it be :

Title: Re: Chemistry
Post by: nid404 on April 07, 2010, 05:48:36 pm
yes ari ur right...
Bromine attached to the carbons across the double bonds....so they'll always be on two different carbon atoms...

@dude-name in black?!?!?! :o
Title: Re: Chemistry
Post by: holtadit on April 07, 2010, 05:55:13 pm
Quote from: nid404 on April 07, 2010, 05:48:36 pm
@dude-name in black?!?!?! :o

did he get banned ?
Title: Re: Chemistry
Post by: nid404 on April 07, 2010, 05:56:56 pm
Quote from: Ari Ben Canaan on April 07, 2010, 05:55:13 pm
did he get banned ?

He banned himself apparently :-\
Title: Re: Chemistry
Post by: Numb on April 07, 2010, 06:16:27 pm
That's what i got

mark scheme says otherwise. :S
Title: Re: Chemistry
Post by: nid404 on April 07, 2010, 06:28:40 pm
Quote from: Numb on April 07, 2010, 06:16:27 pm
That's what i got

mark scheme says otherwise. :S

I'd like to c the qp and ms...
plz upload it here
Thanks
Title: Re: Chemistry
Post by: holtadit on April 07, 2010, 06:32:43 pm
Quote from: nid404 on April 07, 2010, 06:28:40 pm
I'd like to c the qp and ms...
plz upload it here
Thanks

I remeber seeing this question before. I ve done the past papers so many times.

I think they ask only for the molecular formula and not the structural...
Title: Re: Chemistry
Post by: haris94 on April 07, 2010, 06:39:23 pm
Quote from: Numb on April 07, 2010, 06:16:27 pm
That's what i got

mark scheme says otherwise. :S

there could be a typing error or something in the ms
its happened with me b4
Title: Re: Chemistry
Post by: MaNi_DaDuDe on April 07, 2010, 07:22:05 pm
Quote from: nid404 on April 07, 2010, 05:56:56 pm
He banned himself apparently :-\

yes for 59 days. :(