Author Topic: Edexcel CHEMISTRY DOUBTS!!!!  (Read 253481 times)

Offline The Golden Girl =D

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #615 on: December 08, 2010, 11:22:22 am »
C1     -     CH4     -    No other isomers

C2     -     C2H6   -    No other isomers

C3     -     C3H8   -    No other isomers

C4     -     C4H10  -   2 isomers in all

C5     -     C5H12  -   3 isomers in all

C6     -     C6H14  -   5 isomers in all

If you have time, do take a look at the attached powerpoint presentation. It describes all what you need to know in organic chemistry. ;)

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Offline Deadly_king

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #616 on: December 08, 2010, 11:45:10 am »
Jazaka Allahu Kulla kair mate ^_^

Rafwan Oukhtii..... :D

Offline The Golden Girl =D

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #617 on: December 08, 2010, 11:48:01 am »
Afwan Oukhtii..... :D

When An Arab says that you say in return Wa Jazak*

*Jazaki for a girl , Jazakom for a group :)

Afwan is mostly for when someone says Shukran/shukran Jazeelan ;)
Verily, in the remembrance of Allah do hearts find rest(13:28)

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Offline Deadly_king

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #618 on: December 08, 2010, 12:28:16 pm »
When An Arab says that you say in return Wa Jazak*

*Jazaki for a girl , Jazakom for a group :)

Afwan is mostly for when someone says Shukran/shukran Jazeelan ;)

Ooh thanks for the info. :D

But shukran means thanks and afwan is you're welcome, right?

Offline Weaam

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #619 on: December 08, 2010, 02:51:27 pm »
Question:
In june 09 Q8, i dont get why the answer is D?
And Q16 ?
And Q 17?
And Q18 ?
Need help ASAP.
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elemis

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #620 on: December 08, 2010, 03:20:52 pm »
Une momento

elemis

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #621 on: December 08, 2010, 03:22:27 pm »
Can you upload the paper, please ?

Offline The Golden Girl =D

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #622 on: December 08, 2010, 03:52:36 pm »
here it is Ari ,
Verily, in the remembrance of Allah do hearts find rest(13:28)

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

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #623 on: December 08, 2010, 03:54:21 pm »
Question:
In june 09 Q8, i dont get why the answer is D?
And Q16 ?
And Q 17?
And Q18 ?
Need help ASAP.

Q8] If you draw ALL of them you will notice that there are two SIMILAR groups on ONE carbon ( fi kulhom ma3ada D ) so how would you have a geometric isomers ;)

Sorry but that that's what I can do for now i gotta go -.-
« Last Edit: December 08, 2010, 03:56:10 pm by Captain Jack Sparrow »
Verily, in the remembrance of Allah do hearts find rest(13:28)

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elemis

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #624 on: December 08, 2010, 03:54:49 pm »
Okay give me ten minutes.

elemis

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #625 on: December 08, 2010, 03:58:11 pm »
Question 16

The answer is A. This is because all the other options have several electrons in between the outer electron shell and nucleus. This would provide electron shielding which would reduce the first Ionisation Energy.

For answer A the only electron is being tugged on very hard by the strong force of attraction of the nucleus leading to a HIGH 1st IE.

1s1 is obviously Hydrogen.


elemis

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #626 on: December 08, 2010, 04:03:29 pm »
Question 17

v=\frac{nRT}{p}

1gram of ethane = 0.03448 moles

Using above equation :

0.03448 moles * 8.314 * T  / p ; 0.28669*T/p

Doing the same thing for the others you should be able to determine the answer.


elemis

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #627 on: December 08, 2010, 04:08:46 pm »
Question 18

Mg2+ is the answer

Only cations will have lost electrons leading to a fall in ionic radius.

However, anions will gain electrons leading to an increase in ionic radius.

Thus we eliminate A and D.

Now we must choose between Mg and Na.

Mg has more protons than Na. Hence, Mg's nucleus has a greater positive force of attraction which works on its. electrons

When it loses its electrons this RELATIVELY larger force of attraction will attract the outer electrons inwards more than Na can. This will shrink the ionic radius EVEN MORE than Sodium.


elemis

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #628 on: December 08, 2010, 04:13:46 pm »
Question 9

Answer is A.

Bond lengths INCREASE down a group and DECREASE across a row <----- remember this.

Offline Weaam

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #629 on: December 08, 2010, 05:27:11 pm »
Question 16

The answer is A. This is because all the other options have several electrons in between the outer electron shell and nucleus. This would provide electron shielding which would reduce the first Ionisation Energy.

For answer A the only electron is being tugged on very hard by the strong force of attraction of the nucleus leading to a HIGH 1st IE.

1s1 is obviously Hydrogen.


In the mark scheme, its B.
- 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