You are Here: Home

# AQA GCSE Chemistry - C2 & C3 (14th May 2015) watch

1. (Original post by Palette)
You don't actually know who I am.

Anyway

Did you do this?

30+25= 55 cm^3

End temperature- initial temperature= overall temperature (energy) change in the experiment so 32-18= 14 C.

Specific heat capacity of water: 4.2 J/g/C

4.2*5.5*14= 3234 J?
To calculate the energy change wouldn't it be initial temp - end temp?
I know i got 55*20*4.2= 4620J...
2. (Original post by Palette)
You don't actually know who I am.

Anyway

Did you do this?

30+25= 55 cm^3

End temperature- initial temperature= overall temperature (energy) change in the experiment so 32-18= 14 C.

Specific heat capacity of water: 4.2 J/g/C

4.2*5.5*14= 3234 J?
To calculate the energy change wouldn't it be initial temp - end temp?
I know i got 55*20*4.2= 4620J...
3. Did everyone talks bout collision theory in the b2 6 marker and say it reached its optimum temp after 0.7mol/cm3 of concentration because it was 35 degrees for the next three too? C2 was easy, c3 had some strange questions. I'm pretty sure that the overall temperature change was 14 degrees and the mass was 30g of HCL added to the 25g sodium sulfate or whatever it was so the equation was 55 x 14 x 4.2 (assuming the molecular mass was the same as joules as the question said) and the overall energy change was 3234 j or 32.34 kj
4. (Original post by Jules12345)
It was grams and carbon-12
is it not one twelfth Carbon 12 ??
5. guys what did you get for the empirical formula in the C2 paper? I got it wrong and mixed the two divisions at the very beginning up but i did the rest of the question working out right, would i get atleast a mark for that?
6. (Original post by bleeploop)
is it not one twelfth Carbon 12 ??
No because the spec says carbon 12 I think
7. (Original post by LaurenLovesMaths)
For the one about why you'd use a copper alloy in coins instead of pure copper, do you think that 'copper ores are running out so we need to preserve it as much as possible' would be alright?
also copper is quite expensive so would be cheaper to use an alloy
8. (Original post by kiwifruit99)
To calculate the energy change wouldn't it be initial temp - end temp?
I know i got 55*20*4.2= 4620J...
Judge for yourself.
9. (Original post by Clintbarton)
No because the spec says carbon 12 I think
I only put "carbon" for that. Do you think I'll get the mark?
10. I got Pb2O3 but I'm not sure if it's right :/

Posted from TSR Mobile
11. (Original post by liverpoolfan7860)
also copper is quite expensive so would be cheaper to use an alloy
It said do not refer to cost!!
12. (Original post by LashiFire)
I only put "carbon" for that. Do you think I'll get the mark?
No, because carbon has different isotopes which affect the mass, such as carbon-14. I can imagine the mark scheme will say 'carbon by itself insufficient'.
13. (Original post by LashiFire)
I only put "carbon" for that. Do you think I'll get the mark?
Well the carbon in the periodic table has the same atomic mass and number as the one isotopes are measured against (I put 12 6 I think) so probably worthy of a mark, I'm not sure though!
14. (Original post by Palette)
No, because carbon has different isotopes which affect the mass, such as carbon-14. I can imagine the mark scheme will say 'carbon by itself insufficient'.
:/ aw well
15. For the ions question I wrote the ions so like I wrote Fe+2 instead of Iron (II) will that matter?

Posted from TSR Mobile
16. (Original post by camilla_carr)
I got Pb2O3 but I'm not sure if it's right :/

Posted from TSR Mobile
I think thats correct ! thats were I mixed up, i got Pb3O2 and my friend who is amazing at chemistry got your answer so congrats!
17. I can't remember the calculations but I got the right answer:
Pb2 O3
18. (Original post by LashiFire)
I only put "carbon" for that. Do you think I'll get the mark?
'We had better!! i put that too! i reckon they'll give it sure they cant be to picky IUKWIM!
19. (Original post by ambarellarose)
guys what did you get for the empirical formula in the C2 paper? I got it wrong and mixed the two divisions at the very beginning up but i did the rest of the question working out right, would i get atleast a mark for that?
I got PB2O3

Do you remember what you put exactly? (:
20. (Original post by Palette)
Final part correct except 3234 J should be 3.234 kJ not 32.34 kJ.
Typo sorry!! I put 3.234

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: June 15, 2016
Today on TSR

### Tuition fees under review

Would you pay less for a humanities degree?

### Buying condoms for the first time - help!

Discussions on TSR

• Latest
Poll
Useful resources

Can you help? Study Help unanswered threadsStudy help rules and posting guidelines

## Groups associated with this forum:

View associated groups
Discussions on TSR

• Latest

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE