Updates to A-level calculation guides

I have quite significantly enlarged the guides for the calculation topics for the AQA, OCR and Edexcel. It is mostly more worked examples of different sorts of possible calculations.

These are the updated files

AQA 1.2 revision guide calculations

OCR 2.1.3 amount of substance

OCR 2.1.4 acids

Edexcel 5. formulae equations and amount

If you are looking for questions to do you will find them on the  text book page 

 

GCSE revision guides for AQA

I have put together a set of revision guides for the 2018 new AQA GCSE chemistry. They are in syllabus order, which is not the order I teach the course but when it comes to final revision will be the most useful order. It is very much a first draft  for these and no doubt they will change over time.  Find the page here

AQA Paper 3

People have kept asking for a guide on the practicals. As I have explained before I am not producing one. It is worth remembering paper 3 is only partially practical based. There will be multiple choice questions and short answer questions on all parts of the syllabus. There are no short cuts. You need to know everything practical or non practical. It is not going to be an easy paper.

You will need to know the 12 required practicals but you will also get questions on other practicals which may be unfamiliar.

Practical questions could be about:

  • write the method for a common practical
  • draw diagrams of common apparatus
  • create a method for an unusual experiment
  • suggest improvements to a given method
  • state why a step in a method is done
  • draw graphs, take gradients and make conclusions from given results
  • see if results confirm a given hypothesis
  • give expected observations for a reaction
  • write chemical equations that match observations given
  • describing  causes of common errors
  • explain how errors could be minimised
  • explain what effect errors might have on the result

The 12 required practicals for AQA are given below with the relevant revision guides where I have mentioned them.  For some I have included brief methods where I think they are needed but not all. You should refer to your practical work for the full methods or the AQA practical handbook.

1 Make up a volumetric solution and carry out a simple acid–base titration – see 1.2 Calculations and  see 1.25 titrations for lots of questions on errors and method

2 Measurement of an enthalpy change see 1.4 Energetics

Consider – neutralisation reactions, solution plus solid and combustion reactions

3 Investigation of how the rate of a reaction changes with temperature see 1.5 Kinetics

Usually sodium thiosulphate and acid –the result from this experiment can be used to work out activation energy see 1.9 Rate Equations

4 Carry out simple test-tube reactions to identify:

 

5 Distillation of a product from a reaction   see 3.5 Alcohols and 3.14 Synthetic routes

 

 6 Tests for alcohol, aldehyde, alkene and carboxylic acid  see 3.6 Analysis and 3.14 Synthetic routes

7 Measuring the rate of reaction:  see 1.9 Rate Equations or  4. Reaction Kinetics

  •  by an initial rate method – generally ‘clock reactions’ or timing how long it takes for a cross  to disappear
  • by a continuous monitoring method- generally following with a gas syringe, but could be titration of samples or colorimeter

8 Measuring the EMF of an electrochemical cell   see 1.11 Redox Equilibria

9 Investigate how pH changes when a weak acid reacts with a strong base and when a strong acid reacts with a weak base   see 1.12 Acid Base Equilibria

10 Preparation of: 

11 Carry out simple test-tube reactions to identify transition metal ions in aqueous solution see 2.5 Transition Metals  and 2.6. Reactions of Inorganic Compounds in Aqueous Solution

12 Separation of species by thin-layer chromatography see  3.16 Chromatography and 3.13 Amino Acids, Proteins and DNA

Other important experiments commonly asked about in the past that could still well come up:

Simple measuring mass and gas volume experiments such a heating a hydrated salt or measuring the Mr of a volatile liquid see 1.2 Calculations

Colorimeters see 2.5 Transition Metals

Redox titrations and EDTA titrations see 2.5 Transition Metals

Autocatalysis reaction see 2.5 Transition Metals

Measuring an equilibrium constant for an esterification reaction 1.6 Equilibria

Comparing rates of hydrolysis of halogenoalkanes see 3.3 Halogenoalkanes

Any test tube reaction from inorganic or organic part of syllabus

Don’t forget

Calculating uncertainties and safety see 1.2 Calculations

 

 

February updates 2017

A few updates (mostly to AQA notes). Some students have been asking for a practical revision guide. I will not be producing one at the moment. I took the decision to integrate the practical notes into the relevant chapters with the linked theory, and I think this is the best way to approach the practical material. The AQA paper 3 will be a combined practical and synoptic theory paper.

I have done some updates to practical material though, notably in 1-6-revision-guide-equilibria where I have included extensive notes on the practical measuring kc. This is not actually a required practical but it has been a favourite in the past on AQA practical papers. I have also included notes on solving equilibrium constant equations algebraically  which I think are going to appear on the new exams (although not with quadratic equations).

I have changed terminology in 1-2-revision-guide-calculations to use uncertainty instead of error.

The other chapters I have changed have been labelled with (updated February 2017)

I have also produced a aqa-mechanisms-a-level-summary for the new syllabus