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# AQA - Unit 5 - Energetics, Redox and Inorganic Chemistry watch

1. (Original post by lucyanna)
sorry no scanner
Write up the questions
2. (Original post by lucyanna)
sorry no scanner
3. ^^^^^ would be very useful please
4. (Original post by lucyanna)
Seem to have spent the last 2 years waiting for exams/ results and Unis now waiting again!!! If I hear one word of A Levels are getting easier on results day I will scream!!!!! Oh well Gap year at worst and £9000 a year fees thanks to the students friend Nick Clegg and his cronies! Life sucks big time!
hey, can you scan the paper or upload it or something. i wanna c how many q i might have got wrong. thanks
5. 1. enthalpy of lattice formation for calcium fluoride

enthalpy of hydration for fluoride ions

explain the interaction between water molecules and fluoride ions when the fluoride ions become hydrated.

enthalpy sol for caf2 (lattice caf2 =-2611 enthalpy hyd for ca2+ = -1650
enthalpy hyd f- = -506)
6. (Original post by Zakir)
so did i...i think i put water - wasn't thinking at all!
Just a note, you usually won't lose a mark for putting H+ or H2O as the mark schemes usually say ignore them..
7. more you see it the more you're just gonna be worried you got more wrong, the exam is over just leave it up to fate and wait for results day.
Personally I'm more interested as to what people think the grade boundaries are.
8. (Original post by lucyanna)
1. enthalpy of lattice formation for calcium fluoride

enthalpy of hydration for fluoride ions

explain the interaction between water molecules and fluoride ions when the fluoride ions become hydrated.

enthalpy sol for caf2 (lattice caf2 =-2611 enthalpy hyd for ca2+ = -1650
enthalpy hyd f- = -506)
I think instead of doing it on individual post put it all it all in one post, then people on TSR can start deriving the answers!
9. kno3 dissolves in water delta h = + 34.9 delta s= +117 write eqn inc ss for process that occurs when kno3 dissolves in h2o
suggest why entropy change is pos
calc temp at which free-ene delta g is 0
deduce what happens to value of delta g when potassium nitrate diss in h2o at temp lower than answer to last part
what new val of delta g suggest about the dissolving of pot nitrate at this lower temp
10. (Original post by Casshern1456)
Personally I'm more interested as to what people think the grade boundaries are.
The grade boundaries don't really change much for Chem 5; Jan 10, Jun 10 and Jan 11 have been pretty similar. It should be around 70-74 for an A depending on how people did.
11. I honestly thought this paper was the most difficult one I have seen. Lots of questions with different wordings to throw people off, the first page is usually easy but not this time.

Also for the question where it showed those two graphs that shows the voltage or EMF over time; what did you guys put for which cell acts in the same way as the right hand graph, which had a completely straight line?
12. (Original post by Willyg11)
+ 30 something, i got.

and KJ per mol
yes i got +33.6 orsomethingand KJmol^-1 where is this 20.5 coming from?

thought it was mixed ok in parts hard in others. i think i messed up the whole fuel cell question and made silly mistakes but i only need 89 UMS for an A
13. Could anyone tell me how F- ion is dissociated in water ? I mentioned H bonding between F and H but I'm not sure. Another posibilitiy is F- accept electron pair from H2O to form coordinate bonds but it is quite strange as H2OF- is never heard by me before !! Any idea ? It is a 3 mark question, and as you see, I cannot sleeep!
14. Hahahahahaha
I started revising for this at 3am yesterday morning, and I've been awake constantly since
Thursday at 10am .
I thought the exam was pretty easy tbh...
Hopefully got an A.
15. firstly, we FREEEE!!

secondly, chem5 was a testament that aqa ruin lives.
i hated it. even more so when my grade wont be reflective of the amount of effort i put in
99% of me says ahh well, spilt milk. but theres this hugeee twinge of despair

ohhhhh well, i'll get over after i've drank half my weight in koppaberg or something
16. how were you meant to do the find the formation question on the second page???
17. (Original post by lemontang1)
how were you meant to do the find the formation question on the second page???
because it asked for one mole of ammonia...u need to re write the equation so that it makes one mole of ammonia...

so you don't multiply by two (the bond enthalpy of ammonia) like i did...but i think ill get method marks hopefully...
18. (Original post by Zakir)
because it asked for one mole of ammonia...u need to re write the equation so that it makes one mole of ammonia...

so you don't multiply by two (the bond enthalpy of ammonia) like i did...but i think ill get method marks hopefully...
Sorry, I dont mean that one, I meant the one a couple of pages before, where you had enthalpys of dissocation, etc???
19. (Original post by lemontang1)
Sorry, I dont mean that one, I meant the one a couple of pages before, where you had enthalpys of dissocation, etc???
oh you mean the first question?
20. (Original post by Zakir)
oh you mean the first question?
yh

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