# GCSE OCR 21st Century Triple Science (CBP1-7) ThreadWatch

4 years ago
#2501
(Original post by Sulfur)
Change in energy = energy to break - energy to make (or products - reactants) I thought I was right... maybe I'm not!
If it was positive it would've been endothermic that reaction was DEFINATLY exothermic
0
4 years ago
#2502
Thought it was a really easy paper abit too easy and I thought I knew all the answers probably only lost marks on 6 markers or maybe I got alot wrong and thought it was right lol
1
4 years ago
#2503
I just googled it and esterification is a reversible reaction so Mary was correct! Yay!
0
4 years ago
#2504
(Original post by Swag>education)
If it was positive it would've been endothermic that reaction was DEFINATLY exothermic
You don't get marked on the positive or negative energy change. Here is the mark scheme for a energy change question, they ignore the sign.
0
4 years ago
#2505
(Original post by Sulfur)
Masses? The one on the top of the page?

m = c x v
(40x250) / 1000
1000/1000 = 1g

Then for sulphuric acid:

Total mass of sodium hydroxide was 40x2 = 80
Total mass of sulphuric acid was 98
40g given
98(40/80) = 49g
0
4 years ago
#2506
Haber Process 6 marker:
- reactants recycled which means there's a constant supply
- reaction is fast so equilibrium cannot be achieved, unlike in the flask which is why it went so slowly
- pressure in the flask was normal, whereas it's 200 in the haber process and favours the forwards reaction to achieve a higher yield of ammonia
- temperature in the haber process increases the rate of reaction, whereas I guessed the temp in the flask wouldn't have been 450°C so wouldn't have gone fast

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0
4 years ago
#2507
That paper was so easy

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0
4 years ago
#2508
(Original post by Scim)
What did you guys get for the balancing equations question? I ended up with some weird answer as they didn't mark the places where you needed to place the numbers... At least I'll get a mark for the right equation?
The one for butanol ad oxygen? It was one butanol and 5 O2 =4co2 and 5h2o I think
0
#2509
Any predictions on boundaries? It won't be that high because there were some tricky questions, lots of maths and the six markers weren't that difficult but still not that easy to be honest
0
#2510
(Original post by Swag>education)
The one for butanol ad oxygen? It was one butanol and 5 O2 =4co2 and 5h2o I think
I thought it was 6O2 and 4CO2 etc?
0
4 years ago
#2511
I was so happy with that paper!
It was so much easier than I expected
What did everyone else put for the atom economy question?
0
4 years ago
#2512
I quite liked that paper. I think I got most of the short answers and calculations right, but the 3 markers always seem to screw me over. 6 markers were decent, so I'm hoping for about 50/60.

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0
4 years ago
#2513
I got

C4H9OH + 6O2 ------> 4CO2 + 5H2O

For the balanced equation one. Don't know whether this is right or not.
1
4 years ago
#2514
(Original post by Sulfur)
Any predictions on boundaries? It won't be that high because there were some tricky questions, lots of maths and the six markers weren't that difficult but still not that easy to be honest
Since the Jun 2013 was 37 for A*, I'm guessing maybe 41-44 for A*
0
4 years ago
#2515
(Original post by bankruptline)
I got

C4H9OH + 6O2 ------> 4CO2 + 5H2O

For the balanced equation one. Don't know whether this is right or not.
I think I got that too, and it seems to balance, so hopefully we are correct.

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0
4 years ago
#2516
Such an AMAZING paper, wtf>!
0
4 years ago
#2517
(Original post by bankruptline)
I got

C4H9OH + 6O2 ------> 4CO2 + 5H2O

For the balanced equation one. Don't know whether this is right or not.
I got that too, so I hope soo!

What did everybody get for ethanol? I got C2H5OH
0
4 years ago
#2518
(Original post by bankruptline)
I was so happy with that paper!
It was so much easier than I expected
What did everyone else put for the atom economy question?
8/52 x 100 = 15.4
0
4 years ago
#2519
I got that too, so I hope soo!

What did everybody get for ethanol? I got C2H5OH
That's what I put as well. Hopefully that's right :P
0
4 years ago
#2520
What did everyone get for the masses calculation questions?

1) 1g
2) 98 RFM
3) 49
1
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