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Chemistry c2 unit 2 aqa monday gcse 20th new spec

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Original post by Han24
Yes i put this too and I crossed out exothermic - I'm an idiot!!



not sure if i was right, but i wrote about carbon dioxide being a simple molecule and it's intermolecular forces
Original post by shesouttacontrol
not sure if i was right, but i wrote about carbon dioxide being a simple molecule and it's intermolecular forces


I wrote that too :woo:
Reply 183
What did people put for the questions that said describe the structure and bonding or diamond. I couldn't think of 4 marks worth of stuff to write...
Original post by kavym
What did people put for the questions that said describe the structure and bonding or diamond. I couldn't think of 4 marks worth of stuff to write...


I said that diamond is a form if carbon which is attached to four of its neighbours which means it doesn't have any free dlocialsed electrons making it soft. So therefore due to the structure of carbon it is strong there is also covalent bonds joining the carbon together which shows that a lot I energy is needed to break them apart


Posted from TSR Mobile
The carbon dioxide question answer was:

- it's a simple molecule
- there are weak intermolecular forces
- at low temperatures these are forces are broken and so the carbon dioxide becomes a gas
The answer for the ' which gas is produced at the negative electrode' was:
- both potassium and hydrogen are attracted towards the negative electrode
- as hydrogen is the least reactive metal it forms at the electrode
- these hydrogen ions from water become hydrogen atoms and bond to each other, forming hydrogen gas molecules
The answer for the ' explain the structure and bonding in diamond' was:

- Diamond has a giant covalent lattice structure
- There are strong covalent bonds between the carbon atoms as the carbon atoms bond with 4 other atoms
- There are strong covalent bonds between the layers of carbon atoms
- The layers therefore cannot slide over each other making Diamond very hard
The answer for the ' state a pH suitable for sulfuric acid was:

- pH level between '1-6'
Reply 189
Any got the whole qp so we can get an unoffical mark scheme going..
Reply 190
Hi folks,


For the C2 6 mark question, I started talking about the reaction between sodium thiosulphate and HCL.

Now this works in testing the conc of HCL, because you can time the precipitate and therefore work out what conc of HCL is best,

Now ive been told that you had to use magnesium, can anyone confirm this to be true? As I think the question only asked about the rate of reaction of the HCL, and was not specific to what material to use. And the use of material wouldn't matter, as this would be controlled anyway.

So my question would be, would my answer obtain full marks? Or at least, 4/5 marks for not talking about the magnesium, but talking about the change in conc?

I think i should at least get 4 marks, because of taking about repeats, moles of the HCL, identifying the independant variable etc

Regards
Original post by FireDwarf
Hi folks,


For the C2 6 mark question, I started talking about the reaction between sodium thiosulphate and HCL.

Now this works in testing the conc of HCL, because you can time the precipitate and therefore work out what conc of HCL is best,

Now ive been told that you had to use magnesium, can anyone confirm this to be true? As I think the question only asked about the rate of reaction of the HCL, and was not specific to what material to use. And the use of material wouldn't matter, as this would be controlled anyway.

So my question would be, would my answer obtain full marks? Or at least, 4/5 marks for not talking about the magnesium, but talking about the change in conc?

I think i should at least get 4 marks, because of taking about repeats, moles of the HCL, identifying the independant variable etc

Regards


unfortunately for YOU the question did say magnesium
cheers
Reply 192
As I understood it, it was talking about the already set up experiment how you would use that to measure rate of reaction, so you wouldve had to use magnesium.

You may have possibly been able to obtain 3/4 marks, but because you haven't reffered to the magnesium im pretty sure you wouldn't have been able to gain more.
Reply 193
Original post by FireDwarf
Hi folks,


For the C2 6 mark question, I started talking about the reaction between sodium thiosulphate and HCL.

Now this works in testing the conc of HCL, because you can time the precipitate and therefore work out what conc of HCL is best,

Now ive been told that you had to use magnesium, can anyone confirm this to be true? As I think the question only asked about the rate of reaction of the HCL, and was not specific to what material to use. And the use of material wouldn't matter, as this would be controlled anyway.

So my question would be, would my answer obtain full marks? Or at least, 4/5 marks for not talking about the magnesium, but talking about the change in conc?

I think i should at least get 4 marks, because of taking about repeats, moles of the HCL, identifying the independant variable etc

Regards


As I understood it, it was talking about the already set up experiment how you would use that to measure rate of reaction, so you wouldve had to use magnesium.

You may have possibly been able to obtain 3/4 marks, but because you haven't reffered to the magnesium im pretty sure you wouldn't have been able to gain more

Posted from TSR Mobile
Reply 194
As I understood it, it was talking about the already set up experiment how you would use that to measure rate of reaction, so you wouldve had to use magnesium.

You may have possibly been able to obtain 3/4 marks, but because you haven't reffered to the magnesium im pretty sure you wouldn't have been able to gain more


I do agree with the magnesium side, but breading up the mark scheme I see marks for;

1- Mentioning changing the molar of concentration
2- Mentioning Repeating results
3- Mentioning keeping controlled variable the same (eg: same amount of sodium thiosulphate added should get a mark)
4- General mark for the correct method, and explaining how it will show the reaction is going faster.

Do you reckon I should get 4 marks? 3 would be okay, but I think 4/6 would be fair, as im correct, just didnt read it all correctly :/
Reply 195
Original post by FireDwarf
I do agree with the magnesium side, but breading up the mark scheme I see marks for;

1- Mentioning changing the molar of concentration
2- Mentioning Repeating results
3- Mentioning keeping controlled variable the same (eg: same amount of sodium thiosulphate added should get a mark)
4- General mark for the correct method, and explaining how it will show the reaction is going faster.

Do you reckon I should get 4 marks? 3 would be okay, but I think 4/6 would be fair, as im correct, just didnt read it all correctly :/


I think you could possibly get 4 marks dependent on the marker. But it also depends if they specify in the mark scheme whether it has to be linked back to the original experiment, which I suspect it does. Its a bit iffy, and I cant really say what youll get unfortunately! :/

Posted from TSR Mobile
Reply 196
I think you could possibly get 4 marks dependent on the marker. But it also depends if they specify in the mark scheme whether it has to be linked back to the original experiment, which I suspect it does. Its a bit iffy, and I cant really say what youll get unfortunately! :/



Yeah i know, its horrible! Still, I did pretty well on the rest so I guess ill be okay for an A, just means that A* might be gone:/

I do believe that they will, just don't think they will knock off 6 marks for not linking it back, maybe 1 or 2 I agree, but what I said was correct and therefore is worthy of some credit I guess.

I think I can safely say I will get 3 marks for it, so ill go with that, and pray that the examiner feels nice:smile:
Reply 198
anyone got ideas on grade boundaries?

Or if there is a unoffical mark scheme for either of c2 or c3?
I put exothermic too for the first one! I thought this was right..

Also, what was the question that talked about the cake? Why did I tell cake rise and would the reaction need to be heated? :smile:

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