meloj
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So as I mentioned before I'm doing OCR Chemistry A (AS level) and after the f321 exam yesterday, I have a lot riding on this next exam. I'm struggling with memorising all of the reactions and I find the IR and mass spec questions really challenging. I know there is limited time, so I just wanted any advice with the best way to approach learning such a huge amount of information. Everything I've done so far just doesn't seem to be helping me at all, so I wanted to see what other people are doing.

I'm feeling really down about this chemistry exam, the teaching at my school has been really poor. We're on our 4th teacher, and now we're being moved to another school for year 13, half way through our course. It's been so chaotic and now I'm feeling really frustrated, so any help is appreciated

Thanks in advance, hope everyone's revision is going well!
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pineneedles
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Have you tried doing reaction maps? I found them useful for remembering reactions.
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I'd recommend starting by drawing a simple alkane in the middle of a piece of paper and drawing arrows from it, on the arrows you can have reactants and conditions for each reaction, having the product at the end of the arrow
They're really useful for organic chemistry because so many of the products in the reactions we study are the reagents of other reactions. linking them all together helps make them seem less daunting and fix them in your memory (in my opinion anyway!)

What do you find difficult about the mass spec and IR questions? Do you feel like you understand the graphs and what they show or do you just struggle answering the questions?

It's a shame about the way school's going for you, hopefully things will settle down next year.
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meloj
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(Original post by pineneedles)
What do you find difficult about the mass spec and IR questions? Do you feel like you understand the graphs and what they show or do you just struggle answering the questions?

It's a shame about the way school's going for you, hopefully things will settle down next year.
I do understand the graphs, although probably not in enough detail as I haven't got around to revising them in detail yet (I keep pushing it to the bottom of the pile I think 😬)

I Struggle with linking them together when finding the final compound, it just gets really frustrating for me. Although, again that could all stem from my revision on the basics as like I said before, my revision isn't going well at all for chemistry. I find it hard to memorise a lot of the information because I don't really understand it and that makes it harder I think. Chemistry for me so far has been a lot of reading from the book, and trying to make sense of it independently. Is there any websites/methods you thought were helpful?

Thanks for your help, and I also hope it settles down now I'm taking it at a different school. I'm sure it'll be okay, we live and we learn



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pineneedles
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From all of those types of questions I've done, I noticed they give you percentage composition data with the mass spec graph. So in answering this you can find the empirical formula and mass and compare it with the molecular ion peak. So after showing your calculations for the empirical formula, you can state something along the lines of "The empirical mass is equal to the molecular ion peak, so the empirical formula of compound X is the molecular formula" (though of course it won't always be)
You'd get marks for this because you're using the information given to start determining the structure of the compound. The logical step from there would be to use the IR graph to find out what bonds are present between these atoms; "There is a peak in the _____cm^-1 part of the spectrum, showing the presence of a _____ bond so compound X must have this group of atoms :_____"

Sometimes they want you to use fragment ion peaks as these are characteristic of certain compounds. E.g using the fragment ion peaks can help differentiate between an aldehyde and a ketone, as using the molecular formula and IR alone can't do this. If you have the CGP revision guide look at page 77, it explains this if this doesn't make sense.

As for methods.. I'd say make sure you're doing past papers if you haven't started already. you need to make sure you can put what you know into practice. Also, make sure you know the mechanisms we need to remember and are able to draw them out, mechanisms usually form questions that are worth a lot of marks. I'm sorry there's not many other methods I can think of, but doing lots of questions is best I think.

Good luck
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