How can I learn to recognise which calculations need to be used for a question?

I know this sounds silly, but I'm doing AS Chemistry and I'm really struggling to answer questions involving chemical calculations because I don't recognise which calculations need to be used to answer a particular question. It's a problem I have with chemistry generally, actually - I learn the material, but when it comes to actually answering the questions about what I've learnt, I really struggle. This is particularly the case with calculations though.

How can I learn to recognise what is needed to answer a question?

If you have difficulty doing the calculations, then you're probably not understanding the material. It's not enough to learn the material, you need to properly understand what you're learning. Whilst a lot of people learn equations off by heart for calculations in chemistry, I personally think it's a lot more effective just understanding what the calculations involve and extrapolate things from that understanding.

To be honest, I'm not very mathematically minded so I don't really have much of a grasp of what the equations mean, but because my grasp of anything maths-related is so poor, I'm not sure how I can make myself understand them either.

Don't worry my maths is poo too and I'm now doing A2 and I've applied to do chem in uni! Don't let anyone put you down because it! People told me I wasn't capable and I prove them wrong! What I did was kept doing all the questions I could find, so exam questions in text book past papers specimen papers random papers etc. I also wrote things down such as calculations over and over and pretty much memorized the whole textbook! Don't give up it's early days yet just keep trying and most of all always revise whenever you can!


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Don't worry my maths is poo too and I'm now doing A2 and I've applied to do chem in uni! Don't let anyone put you down because it! People told me I wasn't capable and I prove them wrong! What I did was kept doing all the questions I could find, so exam questions in text book past papers specimen papers random papers etc. I also wrote things down such as calculations over and over and pretty much memorized the whole textbook! Don't give up it's early days yet just keep trying and most of all always revise whenever you can!


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Thanks for the response! Would you say you managed to memorise every type of question that could come up in the exam and were therefore familiar with the questions that did come up, or that you managed to develop the skills and understand needed to solve questions you weren't familiar with? Also, what grade did you get at AS if you don't mind me asking?

I would say with OCR (what i did) that memorising every style is difficult since they know what styles they have used before and are always using new styles. It should do to get a decent/borderline grade but if you are aiming for top marks then it wont do :/

Thanks for the response! Would you say you managed to memorise every type of question that could come up in the exam and were therefore familiar with the questions that did come up, or that you managed to develop the skills and understand needed to solve questions you weren't familiar with? Also, what grade did you get at AS if you don't mind me asking?

Buy this book and you'll never look back:
http://www.amazon.co.uk/Calculations-AS-A-Level-Chemistry/dp/0582411270/ref=sr_1_1?ie=UTF8&qid=1388953486&sr=8-1&keywords=chemistry+calculations

Thanks for the response! Would you say you managed to memorise every type of question that could come up in the exam and were therefore familiar with the questions that did come up, or that you managed to develop the skills and understand needed to solve questions you weren't familiar with? Also, what grade did you get at AS if you don't mind me asking?

I would say so most definitely because often the questions are so similar! I was predicted an A but came out with C because both papers were really horrid and we're full of maths but I find AS sooooo easy now! I'd do the calculations for fun! I do AQA btw not sure what exam board your with? However I'm resitting because I know I can do so much better than a C!


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Buy this book and you'll never look back:
http://www.amazon.co.uk/Calculations-AS-A-Level-Chemistry/dp/0582411270/ref=sr_1_1?ie=UTF8&qid=1388953486&sr=8-1&keywords=chemistry+calculations

is there any chance you could post a question that you struggled with?

If you managed to memorize every style that has come up before then why should you have struggled on a paper full of maths? Am i the only one who thinks you cant memorise the style of questions as thats the only thing they really change?

Thanks for the response! Would you say you managed to memorise every type of question that could come up in the exam and were therefore familiar with the questions that did come up, or that you managed to develop the skills and understand needed to solve questions you weren't familiar with?

I would say so most definitely because often the questions are so similar!

Because new questions came up that had never ever come up before! I was very prepared for my exam always had A's in class tests, always had A's in mocks I was awarded the chemistry award for my school! It's just new maths came up that I'd never done before! If new normal questions came up on mechanism or synthesis or interpretation I'd have been fine! Just I was unlucky with the questions that came up and even then I was only a few ums off a B! I'm resitting to get an A. It's different with different people and different exam boards prior to my exam in June 2013 the same style questions were coming up year on year on year! You'd be a fool not to memorise the style and types!


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I really struggled with this question - my boyfriend helped me and I ended up with these workings but I'm still not convinced my answer is correct.

a) Emeralds are a form of the mineral beryl, with their green colour due to the impurities present.
A sample of beryl contains 10.04% aluminium, 53.58% oxygen and 31.35% silicon by mass, with beryllium making up the remainder. Its molecular formula is Al2BexSi6O18.
Find the percentage by mass of beryllium in the compound and hence calculate the value of x in this formula.


10.04 + 53.58 + 31.35 = 94.97%
% by mass(Be) = 100 - 94.97 = 5.03%

Al - 10.04/27.0 = 0.3719/0.3719 = 1
O - 53.58/16.0 = 3.349/0.3719 = 9
Si - 31.35/28.1 = 1.116/0.3719 = 3
Be - 5.03/9.01 = 0.5583/0.3719 = 2

Empirical formula = AlBe2Si3O9

Hence, molecular formula = Al2Be4Si6O18

Value of x = 4

You answer the question with a "definitely"



yet go on to say new questions came up that had never come up before

New questions can come up as you say and trip you up in the exam. Learning the styles is not enough, you need to be confident with the syllabus so that you can work with the given information.



ahh right i see what type of questions you mean now and the technique of writing down the given info and working out which equations to use are less effective in this circumstance. You need to learn the equations well enough so that you can look at a question and know what info you can figure out and then go on to use that info in more equations. The information they give you can vary greatly so you just need to practice being able to see where you are going and not "fumbling around in the dark" for an answer.