Chemistry: Post your doubts here!

[The Sarcastic Retard]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w12_qp_12.pdf

q:17 ... why can't i just cross multiply the number of moles for M? and then use n=mass/Mr to find Mr?
why does it give a different answer?

View attachment 57506

4Na + O2 ---> 2Na2O
n of O2 = 0.0125mol (0.3/24)
so n of Na = 4* n pf O2
so n of Na = 0.05mol
Mass 0f Na = 1.15
Mr = 1.15/0.05 = 23.
Thats correct.

 

[The Sarcastic Retard]

Q38 also?

I am not sure about 34 coz I made a guess.. :3
38.
1) It will form C4O2H8
so answer is C.

 

[Wkhan860]

Electron distribution is usually uniform. At one point, spontaneously, an accumulation happens.
The possibilty of that happening is very less.
So when that accumulation happens, Van der Walls are created. And it increases bp and mp.
If the chance is less, how is it that bp and mp are constant?


awesomaholic101

 

[ahmed butt]

http://papers.gceguide.com/A Levels/Chemistry (9701)/9701_w11_qp_11.pdf Q4 and Q27

 

[The Sarcastic Retard]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s15_qp_12.pdf

the following questions please...

2,9,11,19,20,21,26,29,37

11 is theory part, refer to book.
21 : Its a major product so one Br will be attached to the carbon atom (of = bond) with less hydrogen attached to it.

If I skiped any question do tell me. I was in hurry.

 

[The Sarcastic Retard]

http://papers.gceguide.com/A Levels/Chemistry (9701)/9701_w11_qp_11.pdf Q4?

http://www.compoundchem.com/wp-content/uploads/2014/11/VSEPR-Shapes-of-Molecules.pdf
See 3rd last one..
Hope this helps.

 

[The Sarcastic Retard]

Electron distribution is usually uniform. At one point, spontaneously, an accumulation happens.
The possibilty of that happening is very less.
So when that accumulation happens, Van der Walls are created. And it increases bp and mp.
If the chance is less, how is it that bp and mp are constant?


awesomaholic101

Outta ma mind what is this?? xD

 

[ahmed butt]

http://www.compoundchem.com/wp-content/uploads/2014/11/VSEPR-Shapes-of-Molecules.pdf
See 3rd last one..
Hope this helps.

Q29 ALSO thx for solving in advance

 

[The Sarcastic Retard]

Q29 ALSO thx for solving in advance

dude u wrote 27 above and now u are asking 29. Which one do u want?

 

[Wkhan860]

Outta ma mind what is this?? xD

I got no freaking idea. Its not even relevant but a friend of mine keeps asking abt it.

 

[ahmed butt]

dude u wrote 27 above and now u are asking 29. Which one do u want?

both

 

[The Sarcastic Retard]

both

29) A B C are correct, so D will be wrong.. (D just has one EZ cis trans in the middle)
27) Initiation step involves homolytic bond fission. So 1-chloropropane can take places of 6 hydrogen atom and 2-chloropropane can take only of 2. so ratio is 6 : 2 i.e 3 : 1

 

[The Sarcastic Retard]

I got no freaking idea. Its not even relevant but a friend of mine keeps asking abt it.

Can u ask him to elaborate ?

 

[ahmed butt]

29) A B C are correct, so D will be wrong.. (D just has one EZ cis trans in the middle)
27) Initiation step involves homolytic bond fission. So 1-chloropropane can take places of 6 hydrogen atom and 2-chloropropane can take only of 2. so ratio is 6 : 2 i.e 3 : 1

got it

 

[ahmed butt]

http://papers.gceguide.com/A Levels/Chemistry (9701)/9701_w11_qp_11.pdf
Q34 and 36?

 

[ahmed butt]

http://papers.gceguide.com/A Levels/Chemistry (9701)/9701_w11_qp_11.pdf
Q34 and 36?

 

[The Sarcastic Retard]

I solved this somewhere... I dont remember scroll pages back or type question paper in search and press cntrl F and type 34 and then 36.

 

[ahmed butt]

I solved this somewhere... I dont remember scroll pages back or type question paper in search and press cntrl F and type 34 and then 36.

didnt find

 

[awesomaholic101]

Electron distribution is usually uniform. At one point, spontaneously, an accumulation happens.
The possibilty of that happening is very less.
So when that accumulation happens, Van der Walls are created. And it increases bp and mp.
If the chance is less, how is it that bp and mp are constant?


awesomaholic101

Honestly, i had to read that thrice to get it coz you know, exam mode and all. Interesting, though.
I am assuming that this should just be another "assumption" we make for ease and for study purposes (for example, not all the weight of an object actually acts at the centre of mass) OR that in a huge number of molecules, some or the other molecules must be having a charge so then that is induced to other molecules.
If you find anything about it, let me know.

 

[awesomaholic101]

Electron distribution is usually uniform. At one point, spontaneously, an accumulation happens.
The possibilty of that happening is very less.
So when that accumulation happens, Van der Walls are created. And it increases bp and mp.
If the chance is less, how is it that bp and mp are constant?


awesomaholic101

and btw i didnt get an alert for the tag. :-| how?