Author Topic: some chemistry Questions help please  (Read 1285 times)

Offline aiyla

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some chemistry Questions help please
« on: October 15, 2009, 11:02:12 am »
I got these Questions that i don't know how to answer in a proper way, as an AS level student answer.
so can anyone answer these for me ?

Q1- discuss completely the reaction of HBr with propene . [4]
Q2- what happens when bromine reacts with ethene?, give the mechanism of the reaction. [3]
Q3-what conditions are necessary to manufacture low density poly ethene? ,why it is useful ? [2]
4- write down the structural formula of
     a) Teflon
     b) poly venylethene
     c) PVC
4-b . give the systemic name of the following compounds

1)

2)

3)


i don't know where these Questions are from they were given by my teacher .




Offline Light

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Re: some chemistry Questions help please
« Reply #1 on: October 17, 2009, 03:58:41 am »
Q1:the reaction of HBr and propene is electrophilic addition.The H in HBr has positive dipoles and Br has negative dipoles.The double bond in propene which is nucleophilic attack the HBr bond and The H ions attach to the carbon atom with more hydrogen group according to Markonikoff rule.A carbocation is formed as intermediate.The Br, as electrophile,bind to carbocation and form 1-bromopropane.

Q2:One side of Br will has postive dipoles and other side of Br has negative dipoles.The highly negative double bond attack the bromine molecule and a carbocation is formed.The Br which is poor in electrons will then attack the carbocation and form 1,2-bromoethane.Electrophilic addition mechanism.


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Offline aiyla

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Re: some chemistry Questions help please
« Reply #2 on: October 17, 2009, 09:20:11 am »
thanks,, thats awesome answers .
if its no bother to you .. why, not please ?





nid404

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Re: some chemistry Questions help please
« Reply #3 on: October 17, 2009, 09:22:45 am »
thanks,, thats awesome answers .
if its no bother to you .. why, not please ?




sorry i haven't done organic chemistry as yet

Offline Light

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Re: some chemistry Questions help please
« Reply #4 on: October 17, 2009, 10:08:40 am »
Q3:high pressure via free radical polymerisation.Excellent resistance (no attack) to dilute and concentrated acids, alcohols, bases and esters
Good resistance (minor attack) to aldehydes, ketones and vegetable oils .

Q4:a) F2C=CF2
b)no such thing. only heard before phenylethene .
c)CH2=CHCl

4b 1)2-methylbut-1-ene
2)2-ethylpent-1-ene
3)2-methylprop-1-ene



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nid404

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Re: some chemistry Questions help please
« Reply #5 on: October 17, 2009, 10:44:10 am »
thanks for answering :)