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AS Chemistry 2016 Unofficial Mark scheme

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Original post by FrooshGuitar
Why can't it be below 80%?



Your raw mark can be lower than 80% to get a A just the UMS will make it 80
Reply 101
Avatar for SANTR
SANTR
8
Original post by Engineerrookie
Your raw mark can be lower than 80% to get a A just the UMS will make it 80


What I meant was the raw mark has to be 80% of the total (80). Therefore the lowest mark for an A is 64/80.
Yes your right
Original post by JL9991
You are a complete idiot, it annoys me how somebody can be so stupid, look in the grade boundaries for previous papers, a handful of times around 53/70 has been an A, which is less than 80%. And if you look at the old spec the unit 1 papers were so easy a GCSE student could do them, these papers are undoubtedly harder and 70% seems a fair prediction for an A. As for your point about the papers being harder than others, I disagree massively, they are all pretty much the same difficulty whereas this new spec is harder and also new, which is why the grade boundaries would be lowered.


53 out of 70 was the lowest it's ever been in the past and that's 76% and that has only happened once so your being a little harsh, out of all the years of the old spec average A is 56 which is exactly 80
(edited 7 years ago)
Reply 104
Avatar for JL9991
JL9991
1
Original post by Engineerrookie
53 out of 70 was the lowest it's ever been in the past and that's 78% so your being a little harsh[/
First of all thats 75.7%, and having done every single paper from the old spec in class, 80% of the class was getting over 85% marks in the old spec. We did two sets of specimen papers and the results dropped dramatically - only a fool would argue the old spec is the same difficulty as this spec, you could literally sit any of the papers from the old spec and get over 95% (both unit 1 and unit 2). And secondly, you claim you were talking about UMS mark, yet you quoted someone who said it might be 57 for an A? You must be a complete idiot as clearly this person was talking about marks in the paper...
[QUOTE="JL9991;65241119"]
Original post by Engineerrookie
53 out of 70 was the lowest it's ever been in the past and that's 78% so your being a little harsh[/
First of all thats 75.7%, and having done every single paper from the old spec in class, 80% of the class was getting over 85% marks in the old spec. We did two sets of specimen papers and the results dropped dramatically - only a fool would argue the old spec is the same difficulty as this spec, you could literally sit any of the papers from the old spec and get over 95% (both unit 1 and unit 2). And secondly, you claim you were talking about UMS mark, yet you quoted someone who said it might be 57 for an A? You must be a complete idiot as clearly this person was talking about marks in the paper...



I'm not commenting on difficulty, but believe whatever you want to believe because I know your just getting defensive because you failed that exam, and it sounds like your really depending on those grade boundaries
(edited 7 years ago)
Reply 106
Avatar for Gswp
Gswp
7
Just stop arguing. You can't compare this year's papers to the previous specs enough said.

Regarding old papers, yes paper 1 was always about 80% but for paper 2 there were some papers with a boundary of 69/100
To be honest, I thought that exam was quite challenging, I barely had any time to check it
On the titration question, I wasn't sure whether to only find the mean of the concordant results to find the mean titre :/ I sat there debating for 10 mins, maybe I was overthinking lol
Original post by WhatIsSleep
To be honest, I thought that exam was quite challenging, I barely had any time to check it
On the titration question, I wasn't sure whether to only find the mean of the concordant results to find the mean titre :/ I sat there debating for 10 mins, maybe I was overthinking lol


I did all three of them... But we should get the rest of the marks for the next parts if we carry errors forward, that seems to be how mark schemes work


Posted from TSR Mobile
Original post by IntellectualBoss
MCQ:
balance- 4:7
empirical of hydrocarbon- c3h8
solution neutralised by sulphuric acid- 50cm3 of 1x10dm3
mass of gold 19.3
no2 was brown and forward exothermic
reducing agent- crO7
ionisation energy decreases down group 2
ClF3 is most polar molecule


The question did not ask which molecule was the most polar it asked which one had the strongest dipole, if the difference in electro negativity is large enough even if the molecule is symmetrical wouldn't it still have a strongest dipole because of the way electrons are shared?
No

Posted from TSR Mobile
Original post by marcobruni98
The question did not ask which molecule was the most polar it asked which one had the strongest dipole, if the difference in electro negativity is large enough even if the molecule is symmetrical wouldn't it still have a strongest dipole because of the way electrons are shared?


There is no overall dipole in BF3. The individual dipole moments cancel out
Original post by rayofsunshine98
I did all three of them... But we should get the rest of the marks for the next parts if we carry errors forward, that seems to be how mark schemes work


Posted from TSR Mobile


SAME, I hope I don't lose all 3 marks but my teacher said you'll probably only lose 1-2 and since our answers for part 2 are also 149, then we'll get that.
Why did you guys say was the reason why magnesium has a bigger range between melting point and boiling points than bromine?
Original post by marcobruni98
Why did you guys say was the reason why magnesium has a bigger range between melting point and boiling points than bromine?

It has delocalised electrons, therefore stronger attraction between nucleus and outer electrons and is a metal, whereas the bromine is bonded with vdW forces and so less energy is required to overcome attraction etc.
Original post by marcobruni98
Why did you guys say was the reason why magnesium has a bigger range between melting point and boiling points than bromine?


I said it's because in melting, not all the metallic bonds are broken and only some are broken for the ions to move freely. This means that more temperature can be applied before the metal finally becomes liquid. However, in Br2, once it melts all the van der waals' forces are already broken so the range is likely to be smaller idk lol
Original post by rosemondtan
I said it's because in melting, not all the metallic bonds are broken and only some are broken for the ions to move freely. This means that more temperature can be applied before the metal finally becomes liquid. However, in Br2, once it melts all the van der waals' forces are already broken so the range is likely to be smaller idk lol

I put that metallic bonding is present in the molten metal but not in gaseous metal so all metallic bonds would have to break for this change in state which would require more energy as vdw can exist in both liquid and gaseous states
Original post by marcobruni98
I put that metallic bonding is present in the molten metal but not in gaseous metal so all metallic bonds would have to break for this change in state which would require more energy as vdw can exist in both liquid and gaseous states


Sounds pretty good! We wrote pretty similar things :smile:
Original post by SANTR
Can't be below 80%.


actually it can cus biology has been 68% or lower and i think the same for chemistry
Original post by JL9991
You are a complete idiot, it annoys me how somebody can be so stupid, look in the grade boundaries for previous papers, a handful of times around 53/70 has been an A, which is less than 80%. And if you look at the old spec the unit 1 papers were so easy a GCSE student could do them, these papers are undoubtedly harder and 70% seems a fair prediction for an A. As for your point about the papers being harder than others, I disagree massively, they are all pretty much the same difficulty whereas this new spec is harder and also new, which is why the grade boundaries would be lowered.


lol i know your right and i agree but no need to call the guy an idiot he didnt know simple mistake

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