2016 IGCSE Chemistry Paper 2 Unofficial Mark Scheme 2016

Scroll to see replies

Can i just ask about the incomplete combustion because i got the same as you, it says the same in my cgp book but everyone else says it is just CO + H2O for the products and then balancing obviously.

Reply 181

rcmack

Original post by Nurne

For 2b) It was Iron+ Sulphuric acid -> Iron Sulphate + Hydrogen

And for 4b not meaning to be nit picky but it's Pipette you accidentally put double p.

I apologise for my incompetence. Please forgive me, and I am sorry to all those I have inconvenienced with this mistake.

Reply 182

rcmack

Original post by crazycupcakes

Can i just ask about the incomplete combustion because i got the same as you, it says the same in my cgp book but everyone else says it is just CO + H2O for the products and then balancing obviously.

yea im not sure, hopefully the mark scheme will allow for both answers!
they both could be right, i think the important thing is that carbon monoxide is produced in incomplete combustion :biggrin:

how did the paper go for you?

Reply 183

booksandcats

it was a good paper and seeing tha answers makes me slightly happier and better about it because i wrote most of it down but i'm worried about the grade boundaries tho :tongue:

Reply 184

rcmack

any questions im missing? i think theres still quite a few missed out....

Reply 185

jamesj477

Can anyone tell me what the actual question for 4b - I thought it said what do you use to measure the KOH, so I put measuring cylinder, but people said it was what you use to add it, so it is pipette. Anyone?

Reply 186

crazycupcakes

Original post by rcmack

yea im not sure, hopefully the mark scheme will allow for both answers!
they both could be right, i think the important thing is that carbon monoxide is produced in incomplete combustion :biggrin:

how did the paper go for you?

really good thank you! messed up the last bit where it is 1,500 but other than that no obvious errors :smile:

what about you?

Reply 187

rcmack

Original post by jamesj477

i think it was what would you use to add 25.0cm3 to the conical flask?

Reply 188

jamesj477

Original post by rcmack

i think it was what would you use to add 25.0cm3 to the conical flask?

Ahh damn, I put that then I crossed it out for some reason and put measuring cylinder. Oh well, only 1 mark I guess.
Also for the very las question, I put the right working but I read it off my calculator wrong and put 15,000 instead of 1,500. I'll still get 1 mark if I put 24000 x 0.0625 right?

Reply 189

Lelanor

Original post by rcmack

2a) Water levels rose as oxygen in air reduced as it reacted with iron to produce hydrated iron oxide, stopped as all oxygen had been used up
2b) Cant remember what it asked but it was:
x + y -> iron sulphate + hydrogen
2c) 2HNO3 + CuO -> Cu(NO3)2 + H2O
2d) Warmed acid as it increased rate of reaction
2e) In excess when solid starts to form at the bottom (stops dissolving)

Does anyone remember what 2b was asking about? I can remember the other parts of 2 but not this one. It really doesn't help that I did a past paper an hour before the exam and the two papers are mixed together in my head. Also, the aluminium question might have been the last part of q2, as aluminium and iron are often in questions and parts of the revision guide together.

(edited 7 years ago)

Reply 190

rcmack

Original post by jamesj477

ah that kinda sucks, im sure youll get one mark for working :smile:

and im almost certain that they will give the answer for measuring cylinder to measure out 25cm3, i think they are looking for something that can measure an accurate amount

Reply 191

rcmack

Original post by Lelanor

yea im pretty sure most of the question numbers are mixed up, i just tried to list the questions i remembered

im dumb

Reply 192

jamesj477

Original post by Lelanor

I'm pretty sure it was Sulphuric Acid + Iron

Reply 193

AS1000

is magnesium oxide a base?

Reply 194

Abodee1

Original post by booksandcats

i'm worried about the grade boundaries tho :tongue:

Yes exactly, its going to be really high this year.This is why I always aim really high, even higher than the A* so that i can score it wether its highv or not.

(edited 7 years ago)

Reply 195

rcmack

Original post by AS1000

is magnesium oxide a base?

yes, all metal oxides are alkaline

Reply 196

James the 23rd

I think for methyl orange indicator, in neutral it remains yellow and is 1 drop of acid away from turning red, and does not turn orange, (this is what my teacher told me recently).

Reply 197

Lelanor

Original post by jamesj477

I'm pretty sure it was Sulphuric Acid + Iron

Did you have to fill in some gaps in the word equation? I can picture where this question was on the exam paper and sulphuric acid and iron sound familiar but not what you actually had to do. (Sorry to keep asking about this one question but it's really bothering me that I cant remember if I did it correctly or not)