OCR Chemistry F322~ 4th June 2013~ AS Chemistry

3 A iv I asked the same question too

Thanks genius in advance

theres no 3iv on the paper?

Alkene can form co2 + H2o????

theres no 3iv on the paper?

Page 7 3a (iv)

Oh i think he means the 2013 paper then, he said 2012 lol.

now for the third box, the normal isomer. well the only thing it can be is pent-1-ene. it cant be pent-2-ene because then you'd just be drawing a stereoisomer out again. And you can't branched either because the starting molecule is straight chained.

i hope this all makes sense!

Hi what u said for the normal structural isomer can't be branched ... isn't structural isomers supposed to be chain plus the given skeletal formula is branched? so how should u draw it... if not pent-2-ene

Otherwise... it's amazing thanks for ur help!!!

You said Alkene.. if i am not mistaken..

oh i think he means the 2013 paper then, he said 2012 lol.

So you've got pentan-2-ol which is c5h11oh

when you dehydrate it the formula youre left with is c5h10

start by just writing the c=c

so now you've got 3 carbons left. E/z isomerism is when each carbon is bonded to 2 different groups. So your remaining c3h10 has to be split up into 2 molecules.

The only possibilty is ch3 and c2h5..so now you've got 2 hydrogens left, which are the other 2 atoms left to go on your double bond

so the e isomer would be where each carbon makes one bond to a hydrogen, and one to either the ch3 or c2h5, in opposite directions. So one hydrogen would be on the top left carbon, and the other hydrogen would be on the bottom right carbon. The z isomer would be when both the hydrogens would be on the same side, ie both on the top of each carbon atom or bottom.

The e/z isomers are both pen-2-ene

now for the third box, the normal isomer. Well the only thing it can be is pent-1-ene. It cant be pent-2-ene because then you'd just be drawing a stereoisomer out again. And you can't branched either because the starting molecule is straight chained.

I hope this all makes sense!

its pent-1-ene, so just draw the c=c, then 3 of the bonds would just be hydrogen and the other bond would be c3h7

Sooo need to get a good mark in this for medicine!!! anyone else hoping to apply for medicine?

Oh sorry, you can do complete combustion of an Alkene as well! It's the same principle...

C2H4 + 3O2 -> 2CO2 + 2H2O

sorry out of interest why is there double bond in structural isomers.. when there isn't any in the pentan-2-ol...

Sorry ...

Has anyone made any predictions of what is likely to appear on the paper? Especially for the longer marker questions?

Oh is it... i thought alkenes were for polymer production and things like that..

thanks anyways.. for clarifying.

any compound can have structural isomerism, alkanes, alkenes, anything. as long as the isomers have the same molecular formula, any arrangement of them will give an isomer. there wouldnt be any double bonds in pentan-2-ol because its not an alkene, its an alcohol. the isomers were derived from dehydrating the alcohol (removing a h2o molecule) and therefore a double bond is created.