Chemistry: Post your doubts here!

[SIstudy]

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

Q10(B),25(C),28(D)

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s12_qp_11.pdf

Q28(B),31(B)

See Q31 is B cuz the 3rd statement is completely incorrect, according to ideal gas law
gas molecules have negligible vol
so temp shouldn't really affect the vol here
and the other questions are my doubts as well :/

 

[Suchal Riaz]

THANKS ALOT!!!

if you still have any confusion ask freely.

 

[Youssef Tawil]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w09_qp_12.pdf
Number 20? answer is A how do u know the number of carbon double bonds?

 

[_Ahmad]

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

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

 

[Ahmed Aqdam]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w09_qp_12.pdf
Number 20? answer is A how do u know the number of carbon double bonds?

If all are single bonds then total hydrogen 42 according to the general formula: CnH2n+2O.
1 aldehyde so 2 less H. 1 ring so another 2 less H. Remaining H are 38.
5 double bonds as for every double bond, 2 less H. So remaining are 28.

 

[Suchal Riaz]

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

Q10(B),25(C),28(D)

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s12_qp_11.pdf

Q28(B),31(B)

and one more thing. in question 31 (2) statement is correct because density is proportional to n/V and rearranging equation we get n/v = p/(RT) which shows inverse relation.

 

[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?