F334 (14/01/2013 1:30PM) - Salters Chemistry (Chemistry of Materials) Revision Thread

I'm most likely going to ask for a photocopy as well. I really want to see my mistakes, and if this was really such a straightforward paper as the grade boundaries suggested.

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Can we buy back old papers from last June for example?

Nope, they would've been destroyed by now!

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Good idea! My college are making us get photocopies because half of the students got Us!

We had a couple of students retaking their A2, and all of them got below a C

Salters Chemistry

Oh well, just gotta try that extra hard tbh

I found this a hard paper, but not so hard that i got a Grade D
2 off a c
i really need to get a B overall!! please help me! what revision guides, books, anything do you use??

x

I walked out of that exam knowing I'd only dropped a few marks. I laughed at some of the questions because I knew word-for-word what was going to be written in the mark-scheme. I included all relevant knowledge to support my answers and to show that I wasn't just learning from past-exam questions. I knew I'd lost maybe about 5 marks in it from careless mistakes, but when I opened my result on Thursday I got a D. I'm not one of these chavs that walk out of exams saying 'I've gotten an A' and get my result and get a U. Does anyone else feel like they're in the same position? I was called into the Head of Sixth Form's office on Friday for me to 'explain what happened'. I can't face my Chemistry teacher on Monday. Even though I know he knows what I'm academically capable of, it still angers me that he'll think I got a D in it. In reply to what some of you discussed earlier, OCR do not allow photocopies of your paper, only your original paper back. If you felt, like me, there was a significant error in the marking of the paper, then the only option is to have it re-marked, which I believe costs around £40. OCR is the only exam board who doesn't provide a photocopy of the paper, and is also the most renowned exam board to de-grade papers to reduce the number of A's. If anybody has a copy of the paper or mark scheme, an upload would be much appreciated, thanks.

I know how it feels when you and your teacher both know that you are much more capable than the grade you recieve. It does feel really difficult.

But you have to pick yourself up. When you get your paper back, most likely, it will be your exam technique which might have let you down. I have a feeling this is the case for me; I'm going to practice making my answers more concise.

Use it as a springboard, push and challenge yourself mentally to get the grade you deserve in June.

Good luck



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You get a refund on the remark if the grade changes so if you're so certain that it was a mistake then why don't you get it remarked?

Thanks for the positive advice, but I certainly did not get a D in that exam. I don't mean to sound arrogant, but I went through that paper smiling at how easy it was. There was just one part to a question where you had to draw a diagram that I know I messed up on. Admittedly I can still probably improve on exam technique, but I am 99% certain that the failure lies with OCR on this one, rather than me. My centre's grades always go up around 3 grades when they're re-marked. I know, it's disgusting. That level of poor marking confirms that these aren't just 'mistakes. I'll let you know how much it goes up by when it's remarked.

Thanks for the positive advice, but I certainly did not get a D in that exam. I don't mean to sound arrogant, but I went through that paper smiling at how easy it was. There was just one part to a question where you had to draw a diagram that I know I messed up on. Admittedly I can still probably improve on exam technique, but I am 99% certain that the failure lies with OCR on this one, rather than me. My centre's grades always go up around 3 grades when they're re-marked. I know, it's disgusting. That level of poor marking confirms that these aren't just 'mistakes. I'll let you know how much it goes up by when it's remarked.

I got 2.17g not 21.7.................. I'm sure i've gone wrong as many of you seem to get 21.7 , and as for the 1.2168 or what not , it was because people haven't scaled up the number of moles from 14.0 to 100 dm^3 . Atleast that's what i did initially to get 1.1268.

The reaction was 1:1 moles, and it said that it took 4x10^-3 moles of Sodiumhyrdoxide to react with the Glycoline. ( I believe these were the elements and the 4x10^-3 is remembered from performing a calculation cannot remember very initial values)

So you have 4x10^-3 moles of glycoline to react with , that was in 25cm^3 so you must times by 10 in order to get the correct number of moles for 250cm^3 of the solution . Therefore 4x10^-2 moles in the diluted solution . To calculate the concentration of this solution you divide by 250/1000 because n=cv. I ended up with 0.16 i believe ? (Ok just done the calc , realised it is 21.7 not 2.17 must have not multiplied by ten when i thought i had). So you have 0.16 moldm^-3 solution . This is the diluted solution , so you must multiply by 250/14 in order to gain the concentration of the non diluted solution. This arrives with the answer of 20/7. So you have 20/7 moldm^-3 as a concentration . The concentration of this and the 100cm^3 solution are exactly the same . So from here you multiply by the volume to get the number of moles (20/7 x 100/1000) This gives you 2/7. And moles = mass/relative atomic mass. Therefore 2/7*RAM(Glycoline) which was (76 ?) = the mass. Which is 2/7*76=21.714285grams ............. God damn must have missed the mutiply by ten , but pretty sure that's how you do it for people who got the 1.268 or 12.68 ............ could be wrong .


Calculation :

n=cv for sodium hydroxide = 4x10^-3

4x10^-3 x 10 (because in 25 is 4x10^-3 so in 250 there are 10x)

n/v=c So (4x10^-2)/(250/1000) = 0.16 = c

0.16 x 250/14 (because it is a diluted solution) = 20/7 = c for original mix

n=cv again so 20/7*(100/1000) = 2/7

Then moles = mass/Ram

Ram of the substance was 76

Therefore 76*2/7 = mass = 21.721.714285grams