Author Topic: Edexcel CHEMISTRY DOUBTS!!!!  (Read 253808 times)

Offline red_911

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #915 on: April 25, 2011, 05:14:28 pm »
You mean, three bond pairs and one lone pair...? It's  107.3°.

104.4°

You will find a list of molecules, their shapes and angles  Here

thnkuu ameliaa  :D :D

Offline red_911

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #916 on: April 25, 2011, 09:32:03 pm »
when we talk of alcohols eg ethanol we say that it has london forces and hydrogen bonds but why not permanent di-pole forces as oxygen attached to carbon is more electronegative ?

Offline Malak

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #917 on: April 26, 2011, 12:27:33 pm »
when we talk of alcohols eg ethanol we say that it has london forces and hydrogen bonds but why not permanent di-pole forces as oxygen attached to carbon is more electronegative ?

Well..alcohols do have permanent dipole-dipole interactions other than hydrogen bonding and london forces...but i guess london forces are more significant thats why dipole-dipole isnt mentioned..
Someone else might answer better sorry
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Offline ~ Miss Relina ~

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #918 on: April 26, 2011, 12:51:03 pm »
my doubts :
1. draw the double bond in terms of orbital overlap
2.why the strongest intermolecular forces  in hydrogen halides in liquid form like HCl is van der waals npt permanenet dipole-dipole
i thought of this because HCl is dipolar or does the liqiud means something else


plz guys answer me exams are near
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Offline Malak

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #919 on: April 26, 2011, 01:25:39 pm »
Carry out the preparation of an halogenoalkane from an alcohol and explain why a metal halide and concentrated sulphuric acid should not be used when making a bromoalkane or an iodoalkane

Can anyone explain why?
I know we dont use sulfuric acid as it will oxidise the iodide or bromide ions but what about the Metal halide?

Thx
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elemis

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #920 on: April 26, 2011, 03:26:40 pm »
Carry out the preparation of an halogenoalkane from an alcohol and explain why a metal halide and concentrated sulphuric acid should not be used when making a bromoalkane or an iodoalkane

Can anyone explain why?
I know we dont use sulfuric acid as it will oxidise the iodide or bromide ions but what about the Metal halide?

Thx

Lets say you want to make 1-Chloroethane

You would react NaCl and H2SO4 to get NaHSO4 and HCl fumes. The HCl reacts with ethene to form the deisred product.

Now if you were to repeat the process using NaI and H2SO4  would you get a HI ?? No, you wouldnt. The primary product would be Iodine vapour and not HI.

Hence, the H2SO4 is a very very strong oxidising agent that oxidises the metal halide to its halide molecule.

Where is this question from ?

Offline red_911

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #921 on: April 26, 2011, 03:40:37 pm »
Well..alcohols do have permanent dipole-dipole interactions other than hydrogen bonding and london forces...but i guess london forces are more significant thats why dipole-dipole isnt mentioned..
Someone else might answer better sorry

thanks for ur answer  ;D

Offline Malak

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #922 on: April 26, 2011, 03:52:27 pm »
Lets say you want to make 1-Chloroethane

You would react NaCl and H2SO4 to get NaHSO4 and HCl fumes. The HCl reacts with ethene to form the deisred product.

Now if you were to repeat the process using NaI and H2SO4  would you get a HI ?? No, you wouldnt. The primary product would be Iodine vapour and not HI.

Hence, the H2SO4 is a very very strong oxidising agent that oxidises the metal halide to its halide molecule.

Where is this question from ?

Thx for your reply..
And this is not a question, its a point from the specification :)
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Offline ~ Miss Relina ~

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #923 on: April 26, 2011, 11:25:21 pm »
plz need an answer soon
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elemis

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #924 on: April 27, 2011, 05:09:50 am »
plz need an answer soon


Hint : the longest carbon chain contains 5 carbons.

Offline Aadeez || Zafar

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #925 on: April 27, 2011, 01:50:03 pm »



Yeh BaaabuRaao ka style hein!

Offline EMO123

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #926 on: April 27, 2011, 03:33:51 pm »
thanxx Mr. Must and ari i also got something from this :)

Offline ~ Miss Relina ~

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #927 on: April 27, 2011, 08:26:25 pm »
Hint : the longest carbon chain contains 5 carbons.
Thanks
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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #928 on: April 27, 2011, 08:28:04 pm »


Thanks does this rule applies for all namings of such things
plz if u  can help me with the rules of naming organic structures post anythigappreciating any effort
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Offline The Golden Girl =D

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #929 on: April 28, 2011, 02:04:26 pm »
Thanks does this rule applies for all namings of such things
plz if u  can help me with the rules of naming organic structures post anythigappreciating any effort

Indeed it does.

Here:
the last part here :
http://intro.chem.okstate.edu/1014/Lecture/Organic.html

http://www.chymist.com/organic%20nomeclature.pdf

I hope I helped :)
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