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

Qualification => Subject Doubts => GCE AS & A2 Level => Sciences => Topic started by: Assi1993 on October 04, 2010, 04:19:41 pm

Title: edexcel chemistery question
Post by: Assi1993 on October 04, 2010, 04:19:41 pm
hello all..hows ever1?? i have a ques from JUNE 2010 unit 2 !!....
can any1 pleaseee tell me how is its answer D as its written in the markscheme???
waiting for the reply !!!!
Title: Re: edexcel chemistery question
Post by: nid404 on October 04, 2010, 04:55:49 pm
Branching tends to lower the boiling point since the branching decreases the surface area. Also, straight chain alkanes tend to bind to one another better, so their boiling points are usually higher.
Title: Re: edexcel chemistery question
Post by: Assi1993 on October 04, 2010, 05:07:44 pm
Quote from: Garfield on October 04, 2010, 04:55:49 pm
Branching tends to lower the boiling point since the branching decreases the surface area. Also, straight chain alkanes tend to bind to one another better, so their boiling points are usually higher.

thanks..i know this but...the answer is D according to mark scheme where compound S has higher Boiling point than compound P eventhough compound S is branched?????
Title: Re: edexcel chemistery question
Post by: nid404 on October 04, 2010, 05:16:29 pm
Haloalkanes- Their boiling points are higher than the corresponding alkanes and increase with the atomic weight and increasing no. of halides. This is because the intermolecular forces increase as a result of dipole-dipole interaction because of increased polarity.
Title: Re: edexcel chemistery question
Post by: Assi1993 on October 04, 2010, 05:26:46 pm
Quote from: Garfield on October 04, 2010, 05:16:29 pm
Haloalkanes- Their boiling points are higher than the corresponding alkanes and increase with the atomic weight and increasing no. of halides. This is because the intermolecular forces increase as a result of dipole-dipole interaction because of increased polarity.
ohh ! THAT helped..THANKS ALOT..may God bless u Ameen..!!!!! :)
Title: Re: edexcel chemistery question
Post by: nid404 on October 04, 2010, 05:28:25 pm
Yeah pray for me :D...God doesn't listen to me for some reason :P

You're welcome  :)
Title: Re: edexcel chemistery question
Post by: Assi1993 on October 04, 2010, 05:32:12 pm
Quote from: Garfield on October 04, 2010, 05:28:25 pm
Yeah pray for me :D...God doesn't listen to me for some reason :P

You're welcome  :)

lol dont despair..its okay :D God helps those who helps others  InshaAllah !!
Title: Re: edexcel chemistery question
Post by: nid404 on October 04, 2010, 05:35:01 pm
Quote from: Assi1993 on October 04, 2010, 05:32:12 pm
lol dont despair..its okay :D God helps those who helps others  InshaAllah !!


I don't and hence :P I guess  :D