Chemistry: Post your doubts here!

[itallion stallion]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s10_qp_42.pdf
Can someone plz explain q8'part a,why isn't the answer reaction 1.
Thanks

 

[A star]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s10_qp_42.pdf
Can someone plz explain q8'part a,why isn't the answer reaction 1.
Thanks

it should be 1 i think the ms is wrong!!!!!

 

[itallion stallion]

it should be 1 i think the ms is wrong!!!!!

Thanks a lot!
Can u plz check this too

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w10_qp_43.pdf
Q5a
I can't decide which equation to take for production of oxygen.in the 'Eo for Cl it will be taken as -1.36v
And Eo cell should be then -0.83-(-1.36).but ms gives a different answer.
Thanks!

 

[Logitech]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s08_qp_31.pdf
For question 2f what supporting evidence can I give?

 

[mynameisnotneeded]

Alrighty so who else had P33 today??

 

[mynameisnotneeded]

Can someone give me an estimated grade threshold for the current (2014) chemistry paper 2

Think there is a seperate post for that with a poll. Pls check there. I guess it will be like 40-45 ish
Hardly any organic (but not all people found that one easy) and only periodicity, it would be average...

 

[papajohn]

Alrighty so who else had P33 today??

It was kick ass!

 

[26697luj]

guys anyone has idea about p31?

 

[A star]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s10_qp_42.pdf
Can someone plz explain q8'part a,why isn't the answer reaction 1.
Thanks

daredevil syed1995 your views budy :3

 

[daredevil]

daredevil syed1995 your views budy :3

okay... i am NEVER sure of an answer in a levels but wth ... MY THOUGHTS:

they are talking about the positive electrode a.k.a the anode. oxidation occurs at the anode.
in reaction I Pb is eing oxidised from 0 to +2

In reaction 2, reduction is occuring instead.. Pb goes from +4 to +2

itallion stallion

 

[itallion stallion]

okay... i am NEVER sure of an answer in a levels but wth ... MY THOUGHTS:

they are talking about the positive electrode a.k.a the anode. oxidation occurs at the anode.
in reaction I Pb is eing oxidised from 0 to +2

In reaction 2, reduction is occuring instead.. Pb goes from +4 to +2

itallion stallion

Reaction 1 the answer.

 

[daredevil]

Reaction 1 the answer.

yeah thats what i said.. as oxidation shud occur at the positive electrode, reaction 1 will be the answer bcz oxidation is occuring in reaction 1

 

[itallion stallion]

okay... i am NEVER sure of an answer in a levels but wth ... MY THOUGHTS:

they are talking about the positive electrode a.k.a the anode. oxidation occurs at the anode.
in reaction I Pb is eing oxidised from 0 to +2

In reaction 2, reduction is occuring instead.. Pb goes from +4 to +2

itallion stallion

Can u plz solve this too
http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w10_qp_43.pdf
Q5a
Thanks!

 

[GCE As and a level]

https://www.xtremepapers.com/community/threads/chemistry-9700-p21-gt.33403/#post-770300

GUYS VOTE HERE ABOUT YOUR EXPECTATIONS FOR CHEMISTRY ''GT'' P21

 

[daredevil]

Can u plz solve this too
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w10_qp_43.pdf
Q5a
Thanks!

man i don't exactly remember the equation for O2 O__O x__x

but about the Cl2:
2Cl- --> Cl2 + 2e-

 

[Logitech]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s08_qp_31.pdf
For question 2f what supporting evidence can I give?

 

[itallion stallion]

man i don't exactly remember the equation for O2 O__O x__x

but about the Cl2:
2Cl- --> Cl2 + 2e-

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w10_ms_43.pdf
Tell me why are the electrons written on left hand side for Cl and O2.
The electrode potential for cathode is -0.83v and electrode potential for O2 is -1.23v.the Eo cell should be in bi -0.83+1.23 but this in not correct as per ms.plz help!
Thanks!

 

[daredevil]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w10_ms_43.pdf
Tell me why are the electrons written on left hand side for Cl and O2.
The electrode potential for cathode is -0.83v and electrode potential for O2 is -1.23v.the Eo cell should be in bi -0.83+1.23 but this in not correct as per ms.plz help!
Thanks!

they have SUBTRACTED the electrons .... showing that the ions will lose electrons.
get it??

ummm i don't get wat u r saying about the electrode potential.... uss ka to iss part mein koi kaam nahi tha

 

[daredevil]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w10_ms_43.pdf
Tell me why are the electrons written on left hand side for Cl and O2.
The electrode potential for cathode is -0.83v and electrode potential for O2 is -1.23v.the Eo cell should be in bi -0.83+1.23 but this in not correct as per ms.plz help!
Thanks!

Oohh i get ur point now...

see they have given us the REDUCTION potential as -1.23 but in this cell O2 is being oxidised so it will be -1.23 instead....
so as 1.23 is larger it will be

1.23-(-0.83) instead ) got it?

 

[abruzzi]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w08_qp_4.pdf
Please help me with qn no. 7(d) - both parts. Looks simple but I can't figure it out.
daredevil or anyone else
Thanks