Chemistry: Post your doubts here!

[Mahnoorfatima]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s13_qp_11.pdf q34.?

 

[Mahnoorfatima]

You just have to look at the values of bond energies from the data booklet and see which one is the lowest..

But we don't have the bond energy of C-F? :/

 

[muhammadsaad]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s13_qp_11.pdf q34.?

As we move across the period the ionization energy increses
So the top most peak is of group 8
And the lowest is of group 1 ( shown in the picture)

1 is correct b, j and r are group 8 as highest peak highest ionization across the period

2 is correct as d and l come after lowest peak (group 1) so they are in group 2

3 is correct as g and o are in group 5 and group 5 element have np3 configuration
Take eg of Nitrogen 1s2 2s2 3p3

Phosphorus. 1s2 2s2 2p6 3s2 3p3

P3 means half filled or unpaired electrons

Hope this helps

 

[Dark Destination]

But we don't have the bond energy of C-F? :/

Well, i guess you are supposed to know that C-F will have a comparatively higher bond energy as compared to C-Cl so you don't need to know it's bond energy.
Florine is more electronegative as compared to Chlorine and thus C-F bond is stronger as compared to C-Cl, thus requires more energy to break.

 

[DeadlYxDemon]

Assalamu 3laikum! Firstly I'm really terrible at chemistry, so I've decided to take the exam in the O/N session.
Iz my decision ryt? I mean many of my school teachers say that the checking is strict in O/N session.

 

[princess Anu]

Can somebody highlight those Carbon's

 

[Hinafatima]

I have tried this questions so many times but i am not getting a correct answer. please help.
may june 2014, component 12 Q # 9

 

[Dark Destination]

I have tried this questions so many times but i am not getting a correct answer. please help.
may june 2014, component 12 Q # 9

Link?

 

[Syed Fakhar Hussain]

plz can anyone post good notes of physical chemistry especially bond angles, sp3 hybridization etc??

 

[Mahnoorfatima]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w10_qp_12.pdf q8 ? And what's the general way of solving these kind of question where we have intermediates ?

 

[Hinafatima]

Can somebody help me to explain the way of quoting the link please?

 

[My Name]

plz can anyone post good notes of physical chemistry especially bond angles, sp3 hybridization etc??

Have you tried any youtube videos?
I think they'll help.

 

[Dark Destination]

Can somebody help me to explain the way of quoting the link please?

You have to open the past paper in a new tab, and click on the address bar, and copy the link from there. Then you paste it here.

 

[Fate0]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w10_qp_12.pdf q8 ? And what's the general way of solving these kind of question where we have intermediates ?

The enthalphy change of formation hydrated calcium ions is this.
Ca(s) + aq – 2e– → Ca2+(aq)

So we need to go Ca2+ in the end.
We take Ca(s) and convert them to Ca(g) . Delta H = 177

Now comes the Data Booklet part.
We need to ionise this Ca(g).
First ionisation energy = 590
Second ionisation energy= 1150

Till now we have Ca 2+ (g)

We take that and convert to Ca2+ (aq) for which the energy is -1565.

Add all the energies. 177+590+1150-1565 = +352 which is (D)

In these questions just try to make connection and follow a route. Think about initial states and the final states and then solve it.

 

[Hinafatima]

You have to open the past paper in a new tab, and click on the address bar, and copy the link from there. Then you paste it here.

But on xtreme papers may June 2014 papers are not available , I have just checked it.

 

[Dark Destination]

But on xtreme papers may June 2014 papers are not available , I have just checked it.

You'll have to use a website where they are available.. gceguide something.. is the name of the website with 2014 papers..

 

[Syed Fakhar Hussain]

Have you tried any youtube videos?
I think they'll help.

Ok .Lets give 'em a try !

 

[DeadlYxDemon]

Need Help!!!

- 3 a..
- 3b



- 3 c (ii)
- 3 d (i)
And



- 3 d (ii)

 

[Snow Angel]

Please can someone show as to how to draw the diagram for the following question - q 1d) from: papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w12_qp_52.pdf

Thanks in advance

 

[Bhargav Poudel]

MJ 2004 P1 Q28,30,39. Anyone?