AQA Chemistry C3 - Unofficial Mark Scheme

yh I got that and I practised that a lot in class so Im 100% sure its right

Well, it's a 6 mark quesiton, so you aren't really marked so much on what's correct and isn't but your writing technique for the method.
If everything else is correct, you'll probably only drop one mark as that's only really a minor mistake.

I got the same, the next question said it was endothermic

Arghhh I put the methane one as cows cause I couldn't think of anything 🙈🙈🙈🙈🙈

Did anyone get the one where you had to balance the equation?

Here is the bond energy once and for all:

ethanol + oxygen-->carbon dioxide + water
CH3CH2OH + 3O2 --> 2CO2 + 3H2O

on the left there are:
5*H-C bonds (each with an energy of 413) which totals 2065
1*C-C bonds at 347
1*C-O bonds at 358
1*O-H bonds at 467
3*O=O bonds (each with an energy of 495) which totals 1485
the total left hand side energy is the sum of these at 4722

on the right side there are:
4*C=O bonds (each with an energy of 799 [for CO2]) which totals 3196
6*O-H bonds (each with an energy of 467) which totals 2802
the total right hand side energy is the sum of these at 5998

4722-5998=-1276
it is left as a negative but a positive answer is fine at GCSE

Did anyone get the one where you had to balance the equation?

It was:

CH4 + 2O2 gives C02 + 2H2O

Ah thanks. Was it 1 or 2 marks?

Will you lose a mark for saying 1623 rather than -1623?

Can you remember the question about methane? didn't it already say that its from natural gas and where did that come from? if you remember the question tell me pls

Yeah, I also had that. Did your paper have a specific heat capacity question? I'm seeing calculations for it however on my paper I don't remember a question asking for specific calculations however to compare the fuel of Methane and Decadane or something (I think).

Ah okay thanks
I just really want an A* in chem so I'm hoping stuff like that doesn't have too big of an impact

did anyone else get -342 for the bond energies ...?:/

Filling in table about non metal ion testing: white precipitate in first box, the rest were no change I think
(2 marks)

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What did you get for the bond entalphy question i got 2 thousand something. Also for the catalyst of carboxylic i forgot

Was I correct in saying that the pleasant smell produced was esters? (First question)

Ah okay thanks
I just really want an A* in chem so I'm hoping stuff like that doesn't have too big of an impact