Chemistry: Post your doubts here!

[immie.rose]

Answer is C , but im getting D over and over again. Pls help someone.

 

[immie.rose]

Answer: A

 

[AhsanAfzal]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w10_qp_12.pdf
Q13 how to do this one with oxidation numbers?

 

[Suchal Riaz]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w11_qp_12.pdf

Q4(C),9(D),39(C)

 

[Suchal Riaz]

I will answer rest of questions tomorrow. i gotta sleep now.

 

[_Ahmad]

Answer is C , but im getting D over and over again. Pls help someone.
View attachment 45072

 

[kingo44]

ok sometimes they ask how many structural isomers for moleculat formula c4h80 can we include an ether or only alcohol they said in the question alcohol also any one please ca we include ether

 

[immie.rose]

Ah i get it now, Thanks!!

 

[Najam0096]

CH3CO2CH3 is behaving in the same way as the HCN was behaving with aldehyde
So when you work it out you'll know why the answer is C not B

 

[_Ahmad]

View attachment 45073
Answer: A

Gas X =N02
Gas Y =O2
2Mg(NO3)2 = 2MgO + 4N02 +O2

mass of gas X (NO2) produced =4*(mr of NO2)=4(46)=184
mass of gas Y (O2) produced =mr of O2=32

X/Y=184/32=5.75=1/0.174=5.75

answer = A

 

[Najam0096]

CH3CO2CH3 is behaving in the same way as the HCN was behaving with aldehyde
So when you work it out you'll know why the answer is C not B

Aldehydes have CHO at the end so it cant be B

 

[SIstudy]

View attachment 45074

why isn't the number of moles of H2 taken into account? why only N2? :/ :S

 

[SIstudy]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s12_qp_12.pdf
Q20 (C) plss

 

[Zepudee]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w10_qp_12.pdf

Q40 (D) why?

 

[Hinafatima]

please,may i get helped in q# 29 and 35 for may june 2013 variant 13 , answers are D and C respectively?thanks

 

[Zepudee]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s12_qp_12.pdf
Q20 (C) plss

Propyl ethanoate
Propanol and sodium ethanoate
ch3ch2ch2oh and ch3coona
Mr= 60, Mr= 82
Total product Mr = 142
So, % propanol = 60/142 x 100 = 42.3%
%ch3coona = 82/142 x 100 = 57.7%
Hence, C

 

[kingo44]

Plz attach the link of the year and tell us the number of Q so that we can help u man

When santonin is first treated with warm dilute H2SO4, and then the product of this reaction is
treated with cold acidified KMnO4, a final product X is obtained.

How many atoms of hydrogen in each molecule of product X can be displaced with sodium
metal?
A 2 B 4 C 5 D 6

 

[loveyuan]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w07_qp_1.pdf

9\\21(no sunlight wheyyy)\\33\\37 pleaseeeee

 

[ashcull14]

..

 

[loveyuan]

When santonin is first treated with warm dilute H2SO4, and then the product of this reaction is
treated with cold acidified KMnO4, a final product X is obtained.

How many atoms of hydrogen in each molecule of product X can be displaced with sodium
metal?
A 2 B 4 C 5 D 6

D6
when h2so4 added the -Coo bond ester bond break down and acid and alcohol form
+ col KMnO4 the double bond all gone and form 4 -OH group
sodium can react with acid and alcohol .
each of the acid and alcohol replace by sodium
so 6 of the hydrogen atom