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# OCR B (Salters) F332 Tuesday 4th June 2013 Exam Discussion (Now Closed) watch

1. (Original post by usycool1)

It is hard, but it will be over very soon now. And I'm sure you'll do amazingly!
Aw thank you, I hope so and I'm sure you will too I'm just annoyed with myself because I made quite a few stupid mistakes in unit 1 when it was actually a decent paper so now I have to really make sure I don't mess this exam up! I wish there was an equal split between unit 1 and 2, it's a pain to have so much more to remember for this exam (especially when I find most of it so boring!) But you're right, the exam may be very soon but that also means it will be over very soon!
2. (Original post by Zarah01)
hey guys, really dreading this exam as i gather most of you are -_-
here's the question:

1f. Scientists monitor the composition of the Earth's atmosphere. They have found that the concentration of carbon dioxide in dry, unpolluted tropospheric air has increased from 300ppm to around 380ppm between 1900 and the present day.
i) Taking the present day value to be 380ppm, calculate the increase in the percentage of carbon dioxide in the air between 1900 and the present day.

I converted the values into percentages so,
380/100000=0.0038% and 300/100000=0.0030%
so the difference between these values is 0.008, therefore 0.008/0.003

but according to the mark scheme its meant to be 0.008/8*10^ -3.
Any help would be appreciated, its only one mark but its really frustrating me. Thanks in advance
you are dividing by 100k but it should be 10k ..you're meant to divide by a million then multiply by a 100.. which would basically be dividing by 10k, and the % difference is all they want so they give it as 0.008% or in standard form 8x10^-3
3. (Original post by super121)
It's summed up nicely on page 72 of the CGP revision guide

Thanks
4. (Original post by usycool1)
It's not just oxygen; it could be nitrogen, oxygen or flourine.

Yeah, I know that. But still just say oxygen for exam purposes otherwise you may run out of time, besides the mark schemes allow it.
5. (Original post by ambbs)
Yeah that might have been a slight exaggeration... but this past year has made me absolutely despise chemistry to be honest and I can't wait for this exam to be over - it's the one I've been dreading the most and it's far too soon for my liking!
Exactly. I find direct memorizing of mechanisms and stuff like converting alkene-->alcohol needs phosphoric acid catalyst, steam, night temperature and pressure..... BORING . This part is so ridiculous! Luckily after this exam, chemistry is done
6. (Original post by ambbs)
Aw thank you, I hope so and I'm sure you will too I'm just annoyed with myself because I made quite a few stupid mistakes in unit 1 when it was actually a decent paper so now I have to really make sure I don't mess this exam up! I wish there was an equal split between unit 1 and 2, it's a pain to have so much more to remember for this exam (especially when I find most of it so boring!) But you're right, the exam may be very soon but that also means it will be over very soon!
I know F332 is such a FAT big unit with so much content
7. Btw use chem guide for E/Z isomers topic since the CI book I poor in that topic, while chemguide is much better.
8. One question

What really is oxidation?

It means loss of electrons in Redox. But what does it actually mean in organic chemistry, like saying alcohol oxidises to aldehyde then oxidises to carboxylic acid?
9. I don't understand the MS answer to 3gii in January 2011.
10. (Original post by krisshP)
One question

What really is oxidation?

It means loss of electrons in Redox. But what does it actually mean in organic chemistry, like saying alcohol oxidises to aldehyde then oxidises to carboxylic acid?
I think it still means the loss of electrons however it also converts from aldehyde to carboxylic acid in a reflux

Aldehyde is rcoh
Carboxylic acid is rcooh so there is a loss of electrons

Also for the Advance notice, is there a predicted questions thread- because i need more questions

11. (Original post by krisshP)
I don't understand the MS answer to 3gii in January 2011.
I think it has something to do with chlorine being a halogen, making it quite expensive compared to HCl. It is also highly reactive so would need specialised equipment to handle it.
12. Just to clarify from % to ppbv you x 10,000,000 and divide for vice versa? Thanks.

Oh and could someone explain this wet and dry deposition stuff it's confusing me

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13. Where is the origin of NOx emissions?
Do they mean how NOx is produced by internal combustion, under high pressure the N react with O?
Where is the origin of NOx emissions?
Do they mean how NOx is produced by internal combustion, under high pressure the N react with O?
Yes that's it tbh. You can also mention the burning of traditional fossil fuels, which can release oxides of nitrogen, etc. General knowledge of pollutants from unit 1
15. There is past paper questions on green chemistry. There's been questions about atom economy, percentage yield, building a new plant before which are all in green chemistry
I think it still means the loss of electrons however it also converts from aldehyde to carboxylic acid in a reflux

Aldehyde is rcoh
Carboxylic acid is rcooh so there is a loss of electrons

Also for the Advance notice, is there a predicted questions thread- because i need more questions

http://www.thestudentroom.co.uk/show....php?t=2294388
17. (Original post by SherlockHolmes)
Here are some notes made by the TSR user RebeccaTenney.
thanks man
18. (Original post by krisshP)
http://www.thestudentroom.co.uk/show....php?t=2294388

19. (Original post by krisshP)
Yeah, I know that. But still just say oxygen for exam purposes otherwise you may run out of time, besides the mark schemes allow it.
You have plenty of time in F332 papers

But yeah, true.
20. (Original post by usycool1)
You have plenty of time in F332 papers

But yeah, true.
Really?

Thanks for the good news. I usually can't do one complete paper in timed conditions as they 1hr 45 mins too long for me.

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