[mintaltoids]

24 hours have passed, and there still isn't a thread on the exam-- so I've taken the liberty to make it. What did you guys think of it? I honestly thought P1 was horrific, but P2 was relatively okay.

[arthurhoe123]

Paper 1 was quite easy i thought. Except for 2 question i was unsure. for q 1 i got D which was 6.6x10^23 as there are 11 atoms in there. everyone seem to got ^22 so i am not sure.

And there is one question on wavelength and frequency what did everyone get? i got infrared and infrared

[hemant]

hey arthur its not 6.6 *10^23 or 22....that would be the number of molecules. The answer was A..11 as that is the number of atoms.

[mintaltoids]

(Original post by arthurhoe123)
Paper 1 was quite easy i thought. Except for 2 question i was unsure. for q 1 i got D which was 6.6x10^23 as there are 11 atoms in there. everyone seem to got ^22 so i am not sure.

And there is one question on wavelength and frequency what did everyone get? i got infrared and infrared

First section asked for the shortest wavelength right? I put infrared. Second section asked for the strongest energy? I put ultraviolet. At least I think that's the right answer? The and threw me off though, so I'm not sure if they wanted an answer that included BOTH the shortest wavelength AND the strongest energy. That's not possible right?

[mintaltoids]

(Original post by hemant)
hey arthur its not 6.6 *10^23 or 22....that would be the number of molecules. The answer was A..11 as that is the number of atoms.

I put 11 too! I always get confused between atoms and molecules though, ugh. Let's hope you're right.

[arthurhoe123]

I thought frequency - 1/wavelength
Higher frequency lower wavelength
Since infrared is lower wavelength it should have higher frequency and e=hf h- constant
So it has higher energy?

[MAMDS1993]

Its definitely not 11 guys! 1 mole has 11 x 6.02 x 10^23 atoms and 6.02x10^23 molecules and 0.1 mole will be 0.1 x 11 x 6.02 x 10^23 which gives 6.62 x 10^23 so the correct answer is D! 11 atoms are found in 1 molecule of the substance not 1 mole (6.02x10^23 molecules)!

[MAMDS1993]

it was UV for both of them..higher energy=lowest wavelength hence UV UV!

[arthurhoe123]

Few more interesting question to discuss. The last question about pressure and volume. All three should be true?
There was one question about electrolysis ag+ moves to cu?
And also one question about Kb which I can't specifically remember...

[aeyurttaser13]

Paper 1 was kinda tricky.. I think ill get around a 35.. But paper 2 was amazing, hopefully an 80/90!

[aeyurttaser13]

(Original post by mintaltoids)
I put 11 too! I always get confused between atoms and molecules though, ugh. Let's hope you're right.

Answer can't be 11.. It said total atoms in 0.1 mol, not in 1 molecule. It was D ..

[MAMDS1993]

Yepp All 3 for the last qn I think that was! There was a question that I felt had two answers, the one about the functional groups in that molecule, there was definitely a benzene ring, a carboxylic acid group and an amine..I had to make a choice and put the acid and benzene ring..seemed to be more obvious! What was the Kb question? The electrolysis one I think the direction of ions is opposite to the electron movement, I dont remember the reaction so I dont recall the right answer! Paper 1 was quite bad though in comparison to paper 2 given it takes 35ish out of 40 to score a 7 on it! What was the exothermic reaction?

[MAMDS1993]

I put all 3 since the second one was a neutralisation and the other 2 released gases!

[arthurhoe123]

Does anyone know how many mark the half equation are worth for paper 2 cause I did not get it... Also for enthalpy change I added the lattice enthalpy instead of subtracting it.... What is the maximum mark do you think I can get assuming all other values are right

[MAMDS1993]

paper 2 what did you for the rate of decomposition at something seconds I drew a tangent and found its gradient!

[TTGenius]

(Original post by MAMDS1993)
paper 2 what did you for the rate of decomposition at something seconds I drew a tangent and found its gradient!

yeah, but that's only the first step

you have to change the unit from mms^-1 to cm^3s^-1

[audude]

(Original post by arthurhoe123)
Paper 1 was quite easy i thought. Except for 2 question i was unsure. for q 1 i got D which was 6.6x10^23 as there are 11 atoms in there. everyone seem to got ^22 so i am not sure.

And there is one question on wavelength and frequency what did everyone get? i got infrared and infrared

youve done it right!

[MAMDS1993]

(Original post by arthurhoe123)
Does anyone know how many mark the half equation are worth for paper 2 cause I did not get it... Also for enthalpy change I added the lattice enthalpy instead of subtracting it.... What is the maximum mark do you think I can get assuming all other values are right

2 marks 1 for each! Yeah think you'll get 1 mark out of 2! I got -6 hundred and something for lattice enthalpy similar to what alot of people got! I think I made a mistake about why lattice enthalpy of NaF I drew its bigger, but I think I confused atomic and ionic radius! Did the same for NaF and MgF2 I said its harder to dissociate the Mg into its gaseous ions coz it has twice the charge as that of sodium so takes more energy! I actually considered the whole cycle and since it involves ionisation energy it would automatically affect lattice enthalpy! Why was the volume and the theoretical volume I wrote some of the gas escapes and presence of impurities!

[MAMDS1993]

yeah I did that what did you get?

[MAMDS1993]

I didnt like the carbon dating I mean what the hell for 3 marks? I just wrote used to determine age of plant and animal fossils..apparently it had to do with half-lives!