Chemistry Paper 4-theory- doubts =D

[xhizors]

Asalamualikum
M/J 2012 variant 41 Q3)d) http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s12_qp_41.pdf
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s12_ms_41.pdf
for the structure for A benzene ring is also reduced along with alkene shouldnt it be just alkene reduced ?
but we never studied any reaction of benzene ring with Hydrogen and nickel catalyst :/

well i did!
its like the same reaction as with alkene
with nickel above 160 - 200*C
70-80 atm
Benzene blows offff
now it turns to cyclohexane ==> c6H12

 

[Zari]

well i did!
its like the same reaction as with alkene
with nickel above 160 - 200*C
70-80 atm
Benzene blows offff
now it turns to cyclohexane ==> c6H12

JazakAllah for the reply May Allah bless u

 

[xhizors]

yea i know that...bu-ut for 8 marks i donno how to elaborate...ESP! 'How the catalyst u've chosen helps to decrease the Ea! Please
Jazak allah Khair ! May Allah bless u!

4 marks for each example
1 mark for example
1 mark for telling which type of catalysis it is
1 mark for reaction equation
1 mark for what Cat is doing (except meeeow )
u got the first three i hope so
for the last mark in both example:
a(Iron here is used as increasing the surface area where reagants are adsobed on its surface to increast the number of efficient collisions ...)
b(If Fe2+ is used it will reduce to Fe3+ bu oxidizing peroxydisulfide(s2o8)^2-
the Fe3+ ion now convert I- ions to I2 guys and Fe2+)
for b: the reaction in water is over all slow so homogenous catalysis(Fe2+) introduced to fasten the reaction by stated above(at the end u get Fe2+ ions back)
hope this helps please pray for me

 

[knowitall10]

Assalamu 'Alaykum wa Ra7matullah everyone...
I'm very deeply sorry I couldn't answer your questions...please forgive me
It's just that something went wrong with my application process...and that kinda ruined my day and got me busy.
Please pray that i get accepted to uni...and once again, I'm really very sorry for not answering your questions....

 

[sagystu]

could some one help me s11:qp:41 no. 1 b ..... he used 994 in atomisation of nitrogen while i see it in data booklet 944 !

link to qp http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s11_qp_41.pdf

 

[AlishaK]

4 marks for each example
1 mark for example
1 mark for telling which type of catalysis it is
1 mark for reaction equation
1 mark for what Cat is doing (except meeeow )
u got the first three i hope so
for the last mark in both example:
a(Iron here is used as increasing the surface area where reagants are adsobed on its surface to increast the number of efficient collisions ...)
b(If Fe2+ is used it will reduce to Fe3+ bu oxidizing peroxydisulfide(s2o8)^2-
the Fe3+ ion now convert I- ions to I2 guys and Fe2+)
for b: the reaction in water is over all slow so homogenous catalysis(Fe2+) introduced to fasten the reaction by stated above(at the end u get Fe2+ ions back)
hope this helps please pray for me

for the last one, it's slow cause they both r anions ...that's a right reason too eh?
May Allah bless u mate!! evn if u dnt ask me, I do remember everyone in my prayers... Jazak Allah Khair! btw any tips for app?
Cheerio!

 

[AlishaK]

4 marks for each example
1 mark for example
1 mark for telling which type of catalysis it is
1 mark for reaction equation
1 mark for what Cat is doing (except meeeow )
u got the first three i hope so
for the last mark in both example:
a(Iron here is used as increasing the surface area where reagants are adsobed on its surface to increast the number of efficient collisions ...)
b(If Fe2+ is used it will reduce to Fe3+ bu oxidizing peroxydisulfide(s2o8)^2-
the Fe3+ ion now convert I- ions to I2 guys and Fe2+)
for b: the reaction in water is over all slow so homogenous catalysis(Fe2+) introduced to fasten the reaction by stated above(at the end u get Fe2+ ions back)
hope this helps please pray for me

One more thing. http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w12_qp_41.pdf
Q3 b) do we have to mention NO+1/2O2 in the middle of the two mountains?

 

[Zari]

well i did!
its like the same reaction as with alkene
with nickel above 160 - 200*C
70-80 atm
Benzene blows offff
now it turns to cyclohexane ==> c6H12

Sorry to disturb you again but one thing more for the same Q3)e) why is benzene reacting with excess Br(aq) if any catalyst of FeBr2 isnt present ?
knowitall10 if u know plzz help me with this

 

[knowitall10]

Sorry to disturb you again but one thing more for the same Q3)e) why is benzene reacting with excess Br(aq) if any catalyst of FeBr2 isnt present ?
knowitall10 if u know plzz help me with this

I'll be pleased to help Please tell me which question..

 

[Zari]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s12_qp_41.pdf
http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s12_ms_41.pdf
Q3)e)

 

[knowitall10]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s12_qp_41.pdf
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s12_ms_41.pdf
Q3)e)

it's excess Br2...u use a catalyst when it's not in excess i think. I would take the word "excess" as a hint that no catalyst is needed...

 

[sagystu]

could some one help me s11:qp:41 no. 1 b ..... he used 994 in atomisation of nitrogen while i see it in data booklet 944 ??

link to qp http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s11_qp_41.pdf pleaseeee help !​

 

[Zari]

it's excess Br2...u use a catalyst when it's not in excess i think. I would take the word "excess" as a hint that no catalyst is needed...

so this means whenever excess Br(aq) is mentioned it will always react with benzene ring as well so no catalyst of FeBr2 will be required ?

 

[AlishaK]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w12_qp_41.pdf
Q5 b) third one. Iodoform test, the structure, nd typo reacn. Also lemme know what's the product generally with this test! AND Q5 c (ii) Step 2.
Jazak Allah khair! Please help me soon. knowitall10 or xhizors Anika Raisa anyone?!
Thanks.

 

[Anika Raisa]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w12_qp_41.pdf
Q5 b) third one. Iodoform test, the structure, nd typo reacn. Also lemme know what's the product generally with this test! AND Q5 c (ii) Step 2.
Jazak Allah khair! Please help me soon. knowitall10 or xhizors Anika Raisa anyone?!
Thanks.

wa JazakAllah Khair(un)

 

[AlishaK]

View attachment 26621

wa JazakAllah Khair(un)

Jazak Allah khair! is that CI3? but the MS says something else? So it's necessary for a coupling reacn to have alkaline soln?!
Thanks a ton. Stay blessed!

 

[Anika Raisa]

I just saw the ms n one thing is not clear that is y they used Na when it is not mentioned ! I m cnfused wid dt nw 2!

N abt the ans in 5c yes!

NO problem!the pleasure is mine! Just pray 4 me really worried with chem!

 

[AlishaK]

I just saw the ms n one thing is not clear that is y they used Na when it is not mentioned ! I m cnfused wid dt nw 2!

N abt the ans in 5c yes!

NO problem!the pleasure is mine! Just pray 4 me really worried with chem!

me too. imma pass out anytime. anyhow, bu-ut it's aqueous alkaline NaOH ehh? is that the reason!?

 

[AlishaK]

View attachment 26621

wa JazakAllah Khair(un)

I guess it's supposed to be 'CHI3' ...not sure thou.

 

[Anika Raisa]

May b so .... cz NaOH is alkali but still not justified cz its nt mentioned! they gotta mention to draw dat conclusion!!!

me too. imma pass out anytime. anyhow, bu-ut it's aqueous alkaline NaOH ehh? is that the reason!?