I had a message asking if I was going to give any revision advice and hints about what will be good to learn. I suspect the person was hoping I would have a clairvoyant ability to know what will be in the exam. I am sorry to say I don’t. I will, however, give some general advice about revision.
1. Start now
2. Read, understand and sort your revision notes out first. Understanding is the key to doing well. There are always students who try to succeed at A-level by learning by heart the answer to every past question but don’t understand it. That is not going to get you a high grade. You will meet lots of questions that will involve applying your understanding.
My notes on here were written as memory aids for my students who I had assumed had understood the main concepts in their lessons. So if you read something on my revision notes you don’t understand, you should go back to your lesson work, textbook, teacher for help. I can also recommend http://www.chemguide.co.uk for good explanations.
3. Look at past papers. All the major exam boards have them on their websites. Don’t try to do them as mock exams at the start. Use them to get familiar with the sorts of questions that get asked. When you find questions you can’t do, go back to your notes and try to work out what might be wrong. Are you missing ideas/ facts from your notes? Do you need more explanation?
4. When you are happy with the big concepts start concentrating on finer detail. Make sure you are using the correct definitions- these can vary between exam boards. Do your explanations for things like le Chatelier, reaction rates and ionisation energies have the right detail in them? These tend to be areas people understand but lose valuable marks through sloppy explanations. Do your curly arrows in mechanisms start and end in the right place? The list goes on as there is lots of fine detail and it is crucial you know it. In my experience it is often the fine detail that makes the difference at AS between A and C grades rather than major problems in understanding.
5. Don’t cut corners in your revision. You need to expect questions on everything in the syllabus.
Hi Mr Goalby,
During my trawl of papers I’ve seen a question on Hess’ Law which gives the equation of which we are trying to find the enthalpy of formation of and 3 related equations. What would be the correct method?
Hello Harris, It does rather depend what the equations show. You ought to be able to construct a cycle from all the equations given and apply Hess’s law. I have seen questions where the equations given represented enthalpies of formation or combustion and once you had recognised this you could use the normal method. If you can remember where you saw the question let me know when it was and I can look it up.
June 2008 question 2(c)
APW/Jun08/CHM2
In that question the 3 equations represent enthalpies of combustion of the three substances in the main equation so either construct a hess’s law triangle cycle with the equations or use the equation for enthalpies of combustion. I would not be surprised if a question like that came up.
Hi Mr Goalby
Want to say many thanks for writing concise and superb notes.
However, I am confused in one particular area and would be happy if you could assist me in this matter
My question is on energetic section and topic is the energy change (q) on page 1, you have stated that the unit for the temperature change should be kelvin but in the examples, the units for the temperature had not be converted from degrees to kelvin, which can be done by adding 273 to the degree number. So my question is can you keep the temperature in the degree like its shown in the example or should they be converted in Kelvin.
Many thanks
Mary
I am glad you appreciate the notes.
When doing energetics calculations with temperature change there is no need to convert into kelvin because a 20 degree increase in centrigrade is also a 20 Kelvin rise. e.g. 25C to 45C rise in centigrade is 298 rising to 318 in Kelvin. The difference is the same 20.
I have the understanding now, but just in unit 2 i lose out on like you said the ‘ finer details’ so what do you suggest for that? i know the content, i just lose out on sloppy arrows in the mechanisms and not using the right phrases. I managed to get a B in the mock, but i am aiming for an A.
Look at plenty of past papers and mark schemes. You will find many of the things you are getting a bit wrong frequently come up, so you can start to learn to express yourself in the way the examiners want. Practise drawing out the mechanisms until you get them right. My notes are all written with “what the examiner wants” in mind.
The reaction does not occur