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2016 AQA GCSE Chemistry Unofficial mark scheme 2016

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Thank you this has given me confidence in what i have out + ScienceFanatic
Reply 281
Avatar for Zeeyo
Zeeyo
16
Original post by srmed
Was the two conditions for cracking: high temperature and hot catalyst


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it was pressure not catalyst
Reply 282
Avatar for WaeAM
WaeAM
4
It wasn't Boron it was Neon when explaining what was wrong with the structure. It had 9 electrons, Neon has 7
I said for the two conditions for cracking as:

mixed with steam
high temps

Would I get 2 marks?
Reply 284
Avatar for Ads.m
Ads.m
10
Original post by Zeeyo
it was pressure not catalyst


It was not pressure, it was high temperature and hot catalyst.
Original post by AshWellz
Is this definitely right? I thought potassium would be easier to thermally decompose as its more reactive. I put it didn't thermally decompose because it was more reactive than oxygen so it couldn't be displaced...:s-smilie:


In the results table, potassium didn't even lose mass (or something) so I thought that meant it didn't thermally decompose as easily...
Reply 286
Avatar for Ads.m
Ads.m
10
Original post by romansholiday
I said for the two conditions for cracking as:

mixed with steam
high temps

Would I get 2 marks?


Catalyst need to be one of them i think...You'll get the mark for temp. though.
Reply 287
Avatar for Zeeyo
Zeeyo
16
Original post by Ads.m
Catalyst need to be one of them i think...You'll get the mark for temp. though.


no you got it wrong
Guyzz
Reply 289
Avatar for Ads.m
Ads.m
10
Original post by romansholiday
In the results table, potassium didn't even lose mass (or something) so I thought that meant it didn't thermally decompose as easily...


Thats absolutely correct! It didn't decompose as easily as it need a higher temperature to decompose it. It did mention in the spec that potassium was one of the metals that did not decompose with a Bunsen burner, it need something with a higher temperature.
I think i got around 43-45, would this maybe be an A
For the reactivity one I put any below potassium and calcium can be easily decomposed, as it asked which one could be decomposed easily?
Reply 292
Avatar for Ads.m
Ads.m
10
Original post by Zeeyo
no you got it wrong


Quite sure pressure has nothing to do with it smart guy.
What would the grade boundaries be like?
Original post by Ads.m
Catalyst need to be one of them i think...You'll get the mark for temp. though.


:frown:

On the spec it says catalyst or mixed with steam, I'll ask my teacher tomorrow..
Reply 295
Avatar for Eddiz7
Eddiz7
1
2Fe2O3+ 3C = 4Fe+ 3CO2( 2 marks)

I think the right answer is 2Fe2O3 + 3C = 2Fe2 + 3CO2
Reply 296
Avatar for Ads.m
Ads.m
10
Original post by romansholiday
:frown:

On the spec it says catalyst or mixed with steam, I'll ask my teacher tomorrow..


It asked for two conditions. Mixing the hydrocarbon with steam at a very high temperature was one of the methods and passing the vapours over a hot catalyst was the other method.

Two things in bold were the conditions.
Original post by Ads.m
Thats absolutely correct! It didn't decompose as easily as it need a higher temperature to decompose it. It did mention in the spec that potassium was one of the metals that did not decompose with a Bunsen burner, it need something with a higher temperature.


Yassss, this exam went really well for me, considering I crammed the night before, just little details I've missed out on the six marker and few other questions :smile:
Wouldn't it be smelting instead of thermal decomposition?
Original post by Eddiz7
2Fe2O3+ 3C = 4Fe+ 3CO2( 2 marks)

I think the right answer is 2Fe2O3 + 3C = 2Fe2 + 3CO2


I did this too, like I wrote Fe with a little 2 on the end and balanced from there, wtf :frown:

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