Author Topic: Edexcel CHEMISTRY DOUBTS!!!!  (Read 253473 times)

Offline Amii

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #570 on: December 03, 2010, 10:32:16 am »

By my sweeett nephew ;D

Offline Weaam

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #571 on: December 03, 2010, 10:59:47 am »
I think this is the file - the question paper and the answers both are there

Take care  :D

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Offline Amii

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #572 on: December 03, 2010, 11:10:27 am »
THAAAAAANK YOUUUUUU!! ;DDD
No problem  :D

By my sweeett nephew ;D

Offline Weaam

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #573 on: December 03, 2010, 11:22:03 am »
No problem  :D
Dudee, ur a life saverrrr   ;)
- The man who smiles when things go wrong has thought of someone to blame it on. - Robert Bloch.
-I saw weird stuff in that place last night. Weird, strange, sick, twisted, eerie, godless, evil stuff... and I went in. - Homer
+ Rep me if i have been of any assistance to you ;D

Offline The Golden Girl =D

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #574 on: December 04, 2010, 03:49:08 pm »
I got some doubts in the paper

Q5] , Q9]a)c) , Q11]a) b) .... Q12 ] and 13] ..Q15]e)i) ii)


I'll come back tmrrw if I have any further doubts iA


Thanks :)
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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #575 on: December 04, 2010, 04:39:10 pm »
Ans 5) Ethanol is C2H5OH so it is made up of carbon, hydrogen and oxygen. Carbon exists as a solid in its elemental state so is written as C(s). Hydrogen and oxygen exist as diatomic gases in their standard states so they are written as H2(g) and O2(g) respectively. Then you need to balance the equation but don't forget you are only allowed 1 molecule of your product on the right hand side of the equation.
Hence, the equation would be: 2 C(s) + 3 H2(g) + 0.5 O2(g) --> C2H5OH(l)

So, the answer is D.

9)a) Ionization Energies decreases down the group, the greater the atomic number - size of the atom increases resulting in less nuclear pull.
     So, the answer is A.
   c) Noble gases have filled shells, which is the most stable configuration for an atom. Removing an electron from a noble gas would increase the energy more than if you removed an electron from, for example, nitrogen.
Answer is D (though I'm not sure about this one. :-[)





« Last Edit: December 04, 2010, 04:45:42 pm by Hamlet »

Offline Amii

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #576 on: December 04, 2010, 04:46:36 pm »
Lia the answer for 9c is D but I dont understand why not B  ???

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #577 on: December 04, 2010, 04:56:23 pm »
12) some chlorobromoethane is produced when aqueous bromine reacts with ethene in the presence of sodium chloride, indicating that the  bromine is added to the double bond by slow electrophilic addition before the rapid addition of the chloride ion:

C2H4+ Br2-> C2H4Br++ Br-
C2H4Br++ Cl--> C2H4BrCl

Ans is B.
« Last Edit: December 04, 2010, 04:59:55 pm by Hamlet »

Offline Amii

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #578 on: December 04, 2010, 05:01:00 pm »
13) D

CH3  Cl
 C  =  C
 H     CH3  

Here the high priority ones are Carbon and Chlorine - both are on the same side so Z
The Cl atom is attached to the 2 carbon(as it should get the smallest no possible) so

Z-2-Chlorobut-2-ene

According to me D should be the answer
but C in the ms I dont understand why - Liaaaaaaaaa help  ???
« Last Edit: December 04, 2010, 05:05:48 pm by Sherlock Holmes »

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Amelia

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #579 on: December 04, 2010, 05:18:45 pm »
13) D

CH3  Cl
 C  =  C
 H     CH3  

Here the high priority ones are Carbon and Chlorine - both are on the same side so Z
The Cl atom is attached to the 2 carbon(as it should get the smallest no possible) so

Z-2-Chlorobut-2-ene


It is D, something's up with the markscheme.

According to me D should be the answer
but C in the ms I dont understand why - Liaaaaaaaaa help  ???
[/quote]
« Last Edit: December 04, 2010, 05:32:45 pm by Hamlet »

Offline Amii

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #580 on: December 04, 2010, 05:27:27 pm »
15)ei-
1.20 nanomole dm -3 should be converted to mol cm-3so
since 1 mol = 10-9 nanomol

1.20 * 10 -9

then to covert the dm3
1000 cm3= 1 dm3

1.20 * 10 -9 *10-3

=1.20 * 10 -12 mol dm-3


C=n/V
Volume = 1cm3
so C*n=(1.20*10-12 ) *1 = 1.20*10-12 moles

the Mr of Mg = 24.3
n=m/Mr
m=n*Mr
m=(1.20*10-12 ) * 24.3
=2.916*10-11
=2.92*10-11 g
« Last Edit: December 04, 2010, 05:37:02 pm by Sherlock Holmes »

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Amelia

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #581 on: December 04, 2010, 05:34:46 pm »
11a) it's D.
 Addition reaction of C4H10
b) Ans is C - presence of Double bonds.


Thanks, Mr. Holmes. ;D

Offline Amii

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #582 on: December 04, 2010, 05:40:16 pm »
11a) it's D.
 Addition reaction of C4H10
b) Ans is C - presence of Double bonds.


Thanks, Mr. Holmes. ;D
I should be thanking you Prince hamlet  :D +rep ---- 1 is already pending

thanxxxx liaaaa-love you  ;D

hey check the 15th one - my answering way looks very messy  :(
« Last Edit: December 04, 2010, 05:41:48 pm by Sherlock Holmes »

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Amelia

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #583 on: December 04, 2010, 06:13:12 pm »
I should be thanking you Prince hamlet  :D +rep ---- 1 is already pending

thanxxxx liaaaa-love you  ;D

hey check the 15th one - my answering way looks very messy  :(

It's fine, as long as GG can understand. :P

Offline The Golden Girl =D

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #584 on: December 05, 2010, 03:19:49 pm »
Moi is srry will look at it when I later iA :)
Verily, in the remembrance of Allah do hearts find rest(13:28)

Please, Don't forget to Include GG in your Prayers =D