Chemistry: Post your doubts here!

[_Ahmad]

The part on the OH being added or the number of rings?

Both.

 

[Suchal Riaz]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w04_qp_1.pdf
Q28

the double bond can form between the carbon on which OH is atached and any adjacent carbon.
in (a) and (d) only one product as there is only one adjacent carbon to carbon on which OH is attached
in (b) if the double bond is formed between the 3rd and 2nd carbon then it will have 2 cis-trnas isomers. total 3 products.
in (c) again one product because both products will be same as the molecule is symetrical.

 

[Metanoia]

Sir can you please elaborate Q20

The 2 OH is added with cold dilute KMno4
The red circles are the 2 6-membered ring after hot KMno4 breaks the double bond.

 

[Metanoia]

thats they way i am doing. adding each question one by one. but instead on new post because the answer won't get notification when i add new answer to the same post.

I feel it doesn't matter, since they asked the questions, they should know to check back for the updated answers. But its up to you, whichever is comfortable.

 

[Rockstar RK]

Q8) Use of the Data Booklet is relevant to this question.

The approximate percentage composition of the atmosphere on four different planets is given in
the table below.

The density of a gas may be defined as the mass of 1 dm3
of the gas measured at s.t.p.

Which mixture of gases has the greatest density?


planet major gases / % by number of molecules
A Jupiter H2 89.8, He 10.2
B Neptune H2 80.0, He 19.0, CH4 1.0
C Saturn H2 96.3, He 3.25, CH4 0.45
D Uranus H2 82.5, He 15.2, CH4 2.3

 

[Metanoia]

Q8) Use of the Data Booklet is relevant to this question.

The approximate percentage composition of the atmosphere on four different planets is given in
the table below.

The density of a gas may be defined as the mass of 1 dm3
of the gas measured at s.t.p.

Which mixture of gases has the greatest density?


planet major gases / % by number of molecules
A Jupiter H2 89.8, He 10.2
B Neptune H2 80.0, He 19.0, CH4 1.0
C Saturn H2 96.3, He 3.25, CH4 0.45
D Uranus H2 82.5, He 15.2, CH4 2.3

I'll update this in a while

 

[Suchal Riaz]

Q8) Use of the Data Booklet is relevant to this question.

The approximate percentage composition of the atmosphere on four different planets is given in
the table below.

The density of a gas may be defined as the mass of 1 dm3
of the gas measured at s.t.p.

Which mixture of gases has the greatest density?


planet major gases / % by number of molecules
A Jupiter H2 89.8, He 10.2
B Neptune H2 80.0, He 19.0, CH4 1.0
C Saturn H2 96.3, He 3.25, CH4 0.45
D Uranus H2 82.5, He 15.2, CH4 2.3

the dense gas have heavier Mr.
to overall Mr of "D" is higher. you can calculate it like this:
[82.3%(2)+15.2%(4)+2.3%(16) ]/100=2.62
the average Mr of all others is less. you can check it.

 

[Suchal Riaz]

I'll update this in a while

done

 

[RHB :3]

Ok Last hours left
Can anyone tell me what to study now
I am confused :/

 

[Suchal Riaz]

I'll update this in a while

okay handle the queries for half hour. i will do my own papers during that time. thanks.

 

[Metanoia]

done

ok.

 

[♣♠ Magnanimous ♣♠]

Ok Last hours left
Can anyone tell me what to study now
I am confused :/

what? didn't you study till now

 

[Suchal Riaz]

Ok Last hours left
Can anyone tell me what to study now
I am confused :/

sorry to be rude but all you can do is pray and see the worked solutions of some difficult papers on this thread. so back a few pages and see the questions and their answers.

 

[Suchal Riaz]

what? didn't you study till now

As level is too easy to study. i ahev four papers printed. i haven't done any of them until now.

 

[Metanoia]

Ok Last hours left
Can anyone tell me what to study now
I am confused :/

The most sensible thing to do for the last few hours is to get decent sleep for the brain to process infomation, rather than forgo sleep to cram more stuff.

 

[♣♠ Magnanimous ♣♠]

As level is too easy to study. i ahev four papers printed. i haven't done any of them until now.

than do it na!

 

[♣♠ Magnanimous ♣♠]

The most sensible thing to do for the last few hours is to get decent sleep for the brain to process infomation, rather than forgo sleep to cram more stuff.

but what if you don't know anything in paper? if you study some pages of books it would be more sensible than this suggestion sir

 

[RHB :3]

Yeah but but still have some tome before going to bed
sao what to revise?

 

[♣♠ Magnanimous ♣♠]

Yeah but but still have some tome before going to bed
sao what to revise?

first clear your concepts from book in simpler way it would be better if you read selected chapters like 10 , 11 , 8 . 7 and enthalpy and if time is left than also do organic part

 

[MYLORD]

Moles of H2=0.5
Atoms in one mole=2*0.5*6.02*10^23 (No need to multiply 6.02*10^23 i every step as it is same, just find the ratio)
So here atoms=1

A: 0.5*3=1.5
B: 0.5*5=2.5
C: 1*1=1
D: 1/6*3=0.5

So C has same no of atoms.

thnx bro