The Student Room Group
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>

Equilibria, Energetics and Elements (F325) - June 2011 Exam.

Scroll to see replies

Original post by takethyfacehence
Thank you very much! Great explanation I get what you're saying totally.

No problem :smile:
Reply 161
Avatar for Dunn0
Dunn0
1
Original post by wilsea05
make your own?


I like to compare notes, incase i miss anything........problem?
Original post by Ecstacy.
I hope this papers easier than the old spec papers that i've been practising :eek:

I hope it's easier than the January 2011 paper :redface: and good old F324 of course...
Original post by Salliana23
No problem :smile:


Well Sally, this is strange.
Original post by haydyb123
Well Sally, this is strange.

Ah I should've known you'd be on this thread. Hi Haydn :smile:
How many decimal places/significant figures do you guys round to?
Did a Unifying concepts paper today, it was hard :redface: that is all :sad:
Original post by INeedToRevise
How many decimal places/significant figures do you guys round to?


Default is 3sf, but depends what's in the question.
Reply 168
Avatar for Ecstacy.
Ecstacy.
OP
Original post by blush.ox
Did a Unifying concepts paper today, it was hard :redface: that is all :sad:


I Know ! :redface:
Original post by student777
Default is 3sf, but depends what's in the question.


Thanks :smile:
Anyone read the examiner report for the January 2011 paper? I have a feeling OCR are going to throw us some hard application questions in June :frown:
Reply 171
Avatar for Vidja
Vidja
Did anyone else find the January 2011 paper really difficult? It hasn't been marked yet, but I can't imagine I got above 60%. My confidence has been killed a little, haha.
Original post by Vidja
Did anyone else find the January 2011 paper really difficult? It hasn't been marked yet, but I can't imagine I got above 60%. My confidence has been killed a little, haha.


I haven't done it yet, but apparently it was like 65 for an A so 60 would be a good B!
Original post by Wor Carroll
I haven't done it yet, but apparently it was like 65 for an A so 60 would be a good B!


Yeah in June 2010 an A was 71
Jan 2011 an A was 65
Hey guys. Quick question. I keep messing up my born-haber cycles, the order of my equations is always wrong but I end up with the right answer for the lattice enthalpy or whatever I am supposed to be calculating.
Would I lose marks for the different order of equations? e.g. I put atomisation and then ionisation and the answer is the opposite way.
Original post by INeedToRevise
Hey guys. Quick question. I keep messing up my born-haber cycles, the order of my equations is always wrong but I end up with the right answer for the lattice enthalpy or whatever I am supposed to be calculating.
Would I lose marks for the different order of equations? e.g. I put atomisation and then ionisation and the answer is the opposite way.


It depends on what the mistake is. For example, for NaCl, if you do first ionisation energy of Na, then 1st electron affinity of Cl (instead of the other way round) it doesn't matter (as long as you've already done atomisation first).

However, if you did first ionisation energy of Na, then atomisation of Na, this would lose one or two marks (but not all if you have the right answer). This is because the first ionisation energy means removing an electron from each atom from one mole of gaseous atoms, so if you applied the 1st ionisation energy change to solid Na, this would be wrong.

Sorry this is so long winded! :colondollar:
Original post by Salliana23
It depends on what the mistake is. For example, for NaCl, if you do first ionisation energy of Na, then 1st electron affinity of Cl (instead of the other way round) it doesn't matter (as long as you've already done atomisation first).

However, if you did first ionisation energy of Na, then atomisation of Na, this would lose one or two marks (but not all if you have the right answer). This is because the first ionisation energy means removing an electron from each atom from one mole of gaseous atoms, so if you applied the 1st ionisation energy change to solid Na, this would be wrong.

Sorry this is so long winded! :colondollar:


Hey. Thanks for that :smile:

I'm still a bit confused though :confused: How are you supposed to know to do electron affinity of chlorine first and the atomisation of sodium and then the ionisation energy of sodium. I get that you can't do the ionisation energy before atomisation. But how do you know you are supposed to do atomisation of Cl before atomisation of Na?

Sorry for all the questions :frown:
Original post by INeedToRevise
Hey. Thanks for that :smile:

I'm still a bit confused though :confused: How are you supposed to know to do electron affinity of chlorine first and the atomisation of sodium and then the ionisation energy of sodium. I get that you can't do the ionisation energy before atomisation. But how do you know you are supposed to do atomisation of Cl before atomisation of Na?
Sorry for all the questions :frown:


That's fine! I don't see how you can know which one you do first in that situation so you shouldn't lose any marks.
Reply 178
Avatar for amyyy24
amyyy24
11
Can anyone help with this? I kind of understand it, but don't at the same time (I'm no good with dm/dilutions and all that)

500cm3 of 2moldm-3 of CH3COOH was added to 4g of Li.
Ka = 1.7x10-5
What is the pH of the buffer?

I got as far as knowing there is 1mol of CH3COOH and 0.58mol of Li.

But then my teacher went on to x2 the moles of 0.84 and 1.16 and it all got a bit confusing.

Any help? :smile:
Original post by Salliana23
That's fine! I don't see how you can know which one you do first in that situation so you shouldn't lose any marks.


Oh ok. Thanks for your help :smile:

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you