Chemistry: Post your doubts here!

[zahra azam]

Is there a particular way to measure or find the radius of an ion?

 

[Konstantino Nikolas]

Is there a particular way to measure or find the radius of an ion?

i dont know, there should be ... but i do know that we dont need to know We'll just have to use values from the data booklet if we have to ... all hard work done by someone else

 

[Rizwan Javed]

View attachment 59159

B?

 

[Konstantino Nikolas]

View attachment 59159

are they taking the ratio of the changes or sth? Coz Chlorine's oxdn state is decreasing by 2 and Sulphur's by 4 ...
so its B?

 

[Rizwan Javed]

View attachment 59159

Actually this equation is given wrong here :3

The actual equation should have been :
2ClO3 1- (aq) + SO2(g) → 2ClO2(g) + SO2 4- (aq)

By this equation you'll get the right answer B.

 

[zahra azam]

i dont know, there should be ... but i do know that we dont need to know We'll just have to use values from the data booklet if we have to ... all hard work done by someone else

So they will be in data booklet
Great ^_^
N abt the ionic radius
Its the distance b/w the nuclues and the outershell if the ion
Am i ryt?

 

[Rizwan Javed]

View attachment 59159

This is the actual MCQ from past papers Eugene99

 

[Rizwan Javed]

So they will be in data booklet
Great ^_^
N abt the ionic radius
Its the distance b/w the nuclues and the outershell if the ion
Am i ryt?

I guess.

 

[zahra azam]

I guess.

Ok
N how do we find if we have to add up all energies given in Born haber cycle or subtract them to find lattice energy ?

 

[Konstantino Nikolas]

Ok
N how do we find if we have to add up all energies given in Born haber cycle or subtract them to find lattice energy ?

You should know what energies to use in the born-haber cycle. And to find lattice energy,
Latt energy change = Enthalpy change of formation - (the sum of rest of the energies you use in the cycle)
You will understand better if you try a past paper question on this.

 

[Konstantino Nikolas]

zahra azam ... you could try 42/m/j/14 - Q2d

 

[zahra azam]

You should know what energies to use in the born-haber cycle. And to find lattice energy,
Latt energy change = Enthalpy change of formation - (the sum of rest of the energies you use in the cycle)
You will understand better if you try a past paper question on this.

Hmm
Is it not like lattice energy and the electron affinity= rest of energies on the left side?

 

[zahra azam]

zahra azam ... you could try 42/m/j/14 - Q2d

Thanks buddy tho i do edexcel not cie

 

[Rizwan Javed]

Thanks buddy tho i do edexcel not cie

Is edexcel easier than cie?

 

[zahra azam]

Is edexcel easier than cie?

I will say both stand on the same level
Edx has stuff that u guys have in A2 ...sooo u can guess how it goes for us

 

[Konstantino Nikolas]

Hmm
Is it not like lattice energy and the electron affinity= rest of energies on the left side?

Nope ... don't get yourself confused like that with a particular formula. If you draw the Born-Haber cycle (I hope you know how to?) you will see what needs to be added and subtracted with the arrows ... and this cycle is just a more advanced version of Hess'law so you can can just take the different routes and well, you know, calculate whatever energy you want.

Thanks buddy tho i do edexcel not cie

If you can, find a question in edexcel and do ... or it wouldn't hurt to do this as well ... just practice so you can understand

 

[zahra azam]

Nope ... don't get yourself confused like that with a particular formula. If you draw the Born-Haber cycle (I hope you know how to?) you will see what needs to be added and subtracted with the arrows ... and this cycle is just a more advanced version of Hess'law so you can can just take the different routes and well, you know, calculate whatever energy you want.


If you can, find a question in edexcel and do ... or it wouldn't hurt to do this as well ... just practice so you can understand

Yep thankfully i do know how to draw it xD
Yep i did one of the qs in my book ur way
It works
Thanks

 

[Konstantino Nikolas]

Yep thankfully i do know how to draw it xD
Yep i did one of the qs in my book ur way
It works
Thanks

cool
No problem

 

[donewithtime80]

http://maxpapers.com/wp-content/uploads/2012/11/9701_w13_qp_4.pdf

question 7 d please. need detailed explanations

 

[donewithtime80]

http://maxpapers.com/wp-content/uploads/2012/11/9701_s13_qp_42.pdf

q:8a (iii)..why is that structure?
8c(i): how come there's no reduction in OH?