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2016 IGCSE Chemistry Paper 2 Unofficial Mark Scheme 2016

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Original post by Lelanor
Cgp has an example with just CO and CO2 (and water)
20160615_164236.jpg


methane isn't a long chain though
Original post by Lelanor
Cgp has an example with just CO and CO2 (and water)
20160615_164236.jpg


u missed out the other part of it. it also has C
Reply 82
Original post by Abodee1
Carbon monoxide and water are the only products of incomplete combustion.


CGP has CO2 CO H20 and C
Reply 84
okay then lol. IDK
Original post by Nurne
C8H18 +8 1/2O2 -> 8CO + 9H20


Posted from TSR Mobile


Btw you could have had any combination as long as the "O2" on the left was less than 12.5 and CO was produced on the right, and the entire equation was balanced
Reply 86
Original post by Niclewis
CGP has CO2 CO H20 and C


i think the main ones to put in are CO and H2O and CO2, the combustion of certain substances incompletely may not produce solid carbon
Original post by Niclewis
u missed out the other part of it. it also has C

I mean the bit in smaller text, not in the orange box
Original post by Niclewis
CGP has CO2 CO H20 and C

+ for anyone else in this discussion about incomplete combustion

Here's a past paper for GCSE C1 (I think it was that) where they ask you to balance an equation for incomplete combustion with only CO and water as products
Screenshot_2016-06-15-16-50-49.png
Reply 88
Original post by Lelanor
I mean the bit in smaller text, not in the orange box

+ for anyone else in this discussion about incomplete combustion

Here's a past paper for GCSE C1 (I think it was that) where they ask you to balance an equation for incomplete combustion with only CO and water as products
Screenshot_2016-06-15-16-50-49.png


yea, hopefully they accept both variants
how much is an A*, i think i got 76%
Original post by Lelanor
I mean the bit in smaller text, not in the orange box

+ for anyone else in this discussion about incomplete combustion

Here's a past paper for GCSE C1 (I think it was that) where they ask you to balance an equation for incomplete combustion with only CO and water as products
Screenshot_2016-06-15-16-50-49.png


Because it's methane...
Reply 91
Original post by Talkand...Talk
how much is an A*, i think i got 76%


theres alot of questions missing from the mark scheme tho :/
Original post by Niclewis
i have no idea what you are going on about. You are talking down to people like they have no idea. They will accept red because it does turn slightly acidic FACT


Since it is causing so much controversy between two people, imagine it across the whole population; they should accept both orange and red since personally I think the question wasn't completely clear
Cheers
Original post by Lelanor
They probably didn't realise there were fewer moles of aluminium than electrons and just did 20 x 27 = 540. I think someone I was talking to after the exam said she didn't know how to do it so guessed the method and got that.


If i times it by 3 instead of dividing it by 3, how many marks do you reckon i would get, if any?
Anyone that put just CO2 and H2O got it wrong - the picture taken in the CGP is COMPLETE combustion - this asked for INCOMPLETE COMBUSTION. Aditionally red would be acceptable as I reviewed this w/ my teacher.
Reply 96
any other questions people remember that ive missed out?
Original post by rcmack
any other questions people remember that ive missed out?


you had to read off the burette to get before , after and change
Original post by Lelanor
I got C8H18 + 8.5O2 -> 8CO + 9H20 (my friends agreed but we could be wrong)
I think yours might also be correct, as it's the example given in the CGP revision guide, although I don't think it said anything about producing carbon in the question.

Thank god, people got this. I got exactly this but was questioning myself due to the 8.5, but it balanced out. Also i remember doing a 1c past paper and that had nothing to do with carbon and carbon dioxide , hence i didnt go the cgp route
Original post by Abodee1
Carbon monoxide and water are the only products of incomplete combustion.


no its not. There are 4 products.

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