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

Qualification => Subject Doubts => GCE AS & A2 Level => Sciences => Topic started by: fatal on January 07, 2010, 10:18:13 am

Title: Unit 1 Chemistry...Edxcel Organic
Post by: fatal on January 07, 2010, 10:18:13 am

Can someone tell how to Know if a Alkene is Sysmtrical or unsymitrical
And Difference between Cis -trans and E-Z ismoers

Title: Re: Unit 1 Chemistry...Edxcel Organic
Post by: vanibharutham on January 07, 2010, 10:51:37 am

I assume that when you mean symmetrical you must have Markovnikov's rule at the back of your mind?

anyways,

ill try my best to explain this:

Alkenes can be symmetrical or non symmetrical

Example of a symmetrical alkene is Ethene
It is symmetrical because on each carbon that has a double bond, the constituents are the same.
The way to find out is/.... i guess.. you could draw a line down the double bond, and treat the left side and right side seperately.
If the left and right sides are equal, that is mirror images, then the alkene is symmetrical.

However,
Propene is unsymmetrical

draw a line down the double bond

One of the carbons will have 2 hydrogens attached to it,
while the other will have 1 hydrogen and one methyl group

Hence not symmetrical.



For E/Z isomerism
i really cant explain without drawing anything...
sorry

Title: Re: Unit 1 Chemistry...Edxcel Organic
Post by: nid404 on January 07, 2010, 10:53:32 am

& http://www.knockhardy.org.uk/ppoints.htm
 under organic, click alkenes and then check isomerism


this will help :)

Title: Re: Unit 1 Chemistry...Edxcel Organic
Post by: Ascer Zayan on January 07, 2010, 04:14:30 pm

Thanks Guys Tht Rlly Helped me alot :))