Chemistry Paper 4-theory- doubts =D

[PhyZac]

Look at the previous page PhyZac just explained it. if you still don't get it. Please feel free to ask, I'll be happy to help

Actually I dint. He is asking a different question.

 

[Arpit17]

Actually I dint. He is asking a different question.

yep :|

 

[knowitall10]

Wa eyyaki
I am glad i did.

Now mind telling how to draw it, please? ._.

Lol
K. Draw a huuuuuuggggeeee circle and write C in the middle.
Now draw a circle on one side and label it Cl. do the same with the other side.
draw a cross in both intersections. and one black dot as well.
The black represents C and the x represents Cl. now, the lone pair will be on the C atom. in the empty space. Sorrry, i should've uploaded a photo, but something's wrong with the bluetooth on this stupid laptop. it won't connect to my phone
If u still dnt get it, tell me..

 

[knowitall10]

Actually I dint. He is asking a different question.

it's the same one..OH NO!!!!!!
I'm sorry i thought ur talking abt (a)...alrighty...lemme have a look...or PhyZac wanna explain?

 

[PhyZac]

Lol
K. Draw a huuuuuuggggeeee circle and write C in the middle.
Now draw a circle on one side and label it Cl. do the same with the other side.
draw a cross in both intersections. and one black dot as well.
The black represents C and the x represents Cl. now, the lone pair will be on the C atom. in the empty space. Sorrry, i should've uploaded a photo, but something's wrong with the bluetooth on this stupid laptop. it won't connect to my phone
If u still dnt get it, tell me..

I actually got it very well! Thanks aloooot! Jazaki Allah khairan..!!
May Allah S.w.t have mercy on you and your family and grant you all the highest results in this world and hereafter. Aameen

 

[PhyZac]

it's the same one..OH NO!!!!!!
I'm sorry i thought ur talking abt (a)...alrighty...lemme have a look...or PhyZac wanna explain?

Umm..well you can do it, i am actually on a different paper struggling right now, thanks for the offer though.

 

[knowitall10]

I actually got it very well! Thanks aloooot! Jazaki Allah khairan..!!
May Allah S.w.t have mercy on you and your family and grant you all the highest results in this world and hereafter. Aameen

Umm..well you can do it, i am actually on a different paper struggling right now, thanks for the offer though.

Aameen
Yeah yeah..run away PhyZac ...ok...i'll explain

 

[Zari]

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 :/

 

[PhyZac]

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 why shouldnt it be just alkene reduced ?
but we never studied any reaction of benzene ring with Hydrogen and nickel catalyst :/

Sometimes, you have to evaluate a condition, they wont ask what you have studied....

let you know, H2 and Nickel is so strong reducing agent!

 

[Zari]

Sometimes, you have to evaluate a condition, they wont ask what you have studied....

let you know, H2 and Nickel is so strong reducing agent!

JazakAllah for reply
this means benzene will always be reduced with hydrogen and nickel bcz it acts as a strong reducing agent and i guess with ketone as well ?

 

[sagar65265]

what about b(i) and (ii)??

For the second row, for the value of [CH3OH], look at the stoichiometric equation; for every mole of CH3CHO used up in the reaction, two moles of CH3OH will be used up. Therefore if the volume remains constant, the concentration can be written in proportion to the number of moles of each molecule at equilibrium.

If x moles of CH3CHO are used up once equilibrium has been reached, twice that number of moles, i.e. 2x moles of CH3OH will be used up to reach equilibrium. Since the volume is constant, the concentration can written in terms of 2x; the original concentration of CH3OH is 0.10 mol dm^-3, so the final concentration will be (0.10 - 2x)mol dm^-3.

The concentration of [H+] remains constant since it is written in the stoichiometric equation as a catalyst, and the concentration/amount of catalyst in the beginning of an experiment will be the same as it is at any other point, because the catalyst itself doesn't take part in the reaction (it usually has a role to play i the reaction mechanism, but if it is indeed used up, it will be regenerated at the end of the mechanism).

Since the number of moles of H2O produced is equal to the number of moles of Acetal A, the concentration of water in the solution will be equal to x.

For the next part, just substitute the value of 0.025 for x, as is given in the table, to get the answers.

Hope this helped!

Good Luck for all your exams!

 

[PhyZac]

JazakAllah for reply
this means benzene will always be reduced with hydrogen and nickel bcz it acts as a strong reducing agent and i guess with ketone as well ?

Yup very well...

actually...some questions states what reduces ketone but not alkene, then say NaBH4 ..since H2 and Ni does for both.!

 

[Zari]

Yup very well...

actually...some questions states what reduces ketone but not alkene, then say NaBH4 ..since H2 and Ni does for both.!

JazakAllah for clearing this out
May Allah Bless u always Good Luck for the exams as well

 

[Arpit17]

yeah kinda helped! Thanks mate,good luck to you too!!

 

[Arpit17]

sagar65265 got time for this one? http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s11_qp_41.pdf qn 4(iv)..??

 

[railey]

Salaam alaykum,
Can someone please help me with balancing a equation using oxidation numbers please.

 

[AlishaK]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w12_qp_41.pdf
Q3 ii) i forgot.
knowitall10 to the rescue?! Please...
Jazak Allah Khair!

 

[xhizors]

xhizors
Answer:
Because MnO4- ions must convert to Mn2+.
They are acting as oxidising agents since they convert Fe2+ to Fe3+

aren't they getting converted in 4H+ one equation ??

 

[xhizors]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w12_qp_41.pdf
Q3 ii) i forgot.
knowitall10 to the rescue?! Please...
Jazak Allah Khair!

one Haber Process Reaction Heteregenous Catalysis example(Fe is used as adsorption )
other one is for Sulfide and iodide reaction (fe used for Redox reaction in a same state)

 

[AlishaK]

one Haber Process Reaction Heteregenous Catalysis example(Fe is used as adsorption )
other one is for Sulfide and iodide reaction (fe used for Redox reaction in a same state)

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!