Advice for A level Chemistry students

Well done – you have completed your GCSEs and been accepted onto the A level Chemistry course at your school or college!

In approximately 22 months from your start in September, you will have completed your 3 A level exams and be waiting for your results in the August.

  • How can you use those 22 months most effectively?
  • How can you give yourself the best chance to achieve?

Topics of Year 12 & 13 – where to start? Ìý

Most schools and colleges follow roughly the same topic order if they work with 1 or 2 teachers taking your class. This tends to follow the previous ‘AS topics order’ and then complete the ‘A2 order’. This allows for a graded start in Year 12, with a review and recap in Year 13.

Several topics in Year 12 are very similar to your GCSE courses e.g.Ìý Topics on Kinetics (Rates of reactions) and Equilibrium.

Topics such as Atomic structure, Amount of substance, Bonding, and Energetics (energy change) start the A Level course based on your previous GCSE work .

This means that you will need a good understanding and review of your GCSE work before you begin these topics. Going forward into Year 13, it is again important to review the Year 12 topics before you begin their extension topics Ìý– a very useful and positive working habit to get into.

Mathematical areas of work

There are lots of mathematical topics in the Chemistry A level ( ~20% of the marks). This can often cause more concern than it needs to.

The maths involved is of the same level as higher level GCSE maths. This will be basic addition, subtraction, multiplication and division alongside ratio work, straight line graph work.

Classics in any science work is the re-arrangement of equations and making sure you have the correct units for your calculations. Also, you will have some algebra work in some of the more complex equations questions.

From experience, the actual individual maths actions involved in the majority of the questions is not the main problem, but the holistic overview of the question is. Students need to realise that they have to perform those actions, and then importantly it’s the detail you explain those in the answer needs to show CLEAR WORKING OUT.

My advice to students is to be clear and organised with your answers and write down WORDS to go alongside your number for a calculation. You may not need it all, but you are writing out an answer for the marks, as much as for yourself.

Simple Maths example

This has division/ratio/multiplication, but putting it together is more complex.

e.g.ÌýÌýÌýÌýÌý If I start with 10 grams of NaOH how many grams of Na2SO4 will I make?

2 NaOHÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌý +ÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌý H2SO4ÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌý ® Na2SO4 ÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌý + ÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌý 2 H2O

This example shows how you should always make sure all your steps are clear.

  • Equations first, then numbers
  • Show working out and clarity for where numbers come from
  • Show steps in calculation individually and clearly

This is good practice for any calculation and working through Year 12, and more so in Year 13.

Organic Chemistry in A level

This is always a very large and important part of the course and is generally very new and different from GCSE work.

There are some core aspects of this work that you need to make sure to learn and understand from the outset as and when you meet them.

Formula of organic compounds

It is important to learn the different types of formula and when they are best used:

We will use Ethane as an example compound going through the formula types:

Empirical formula

The simplest whole number ratio of the atoms in the compound – e.g. CH3

(used in determining formula and from analysis of empirical formula data)

Molecular formula

The total number of each atom in the compound formula – C2H6

(used rarely as not very informative- combustion reactions one of few times used)

Structural formula

Showing how the atoms are grouped together around each C in the compound-CH3CH3

(solid information about the compound which has some important information which can be used in chemical equations)

Displayed formula

Shows all the atoms and bonds present in the compound

Very clear and informative, used when drawing out mechanisms and showing polarisation on compounds.

Skeletal formula – NEW for A level

A ‘simplified’ way of drawing out the compound showing the C-C bond as a line and NOT showing any C-H bonds or H atoms.

Ethane C2H6ÌýÌý Ìý ÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌý Or butane C4H10

Functional groups

These are the parts of the organic compound which are not just the C and H in an Alkane.

These give the compound its specific properties and determine how it reacts and interacts with other compounds.

You need to be able to spot these functional groups from the different formulas you can get.

e.g. AlcoholÌýÌýÌýÌýÌýÌý Ìý ÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýAldehyde

There are lots of these you come across in Year 12 and some more in Year 13. It is useful to make sure you learn them all as soon as you can and don’t get surprised by them.

Reaction chemical equations

These show what happens in the chemical equation with the reactants, and then any catalysts or conditions needed for the reaction over the arrow between the reactants and products.

e.g. ÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýin ethanol

ChloromethaneÌýÌýÌý +ÌýÌý AmmoniaÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌý MethylamineÌýÌýÌý +ÌýÌý Ammonium Chloride

CH3ClÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌý +ÌýÌýÌý 2NH3ÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌý CH3NH2ÌýÌýÌýÌýÌýÌýÌýÌýÌý +ÌýÌý NH4Cl

Mechanisms

These are always areas which cause concern at first, but need to be LEARNT and UNDERSTOOD as you go through the course. Depending upon your Exam board, you will have a slightly different number of these to cover, but they all follow the same rules.

  • Use the key part of the reactants – Nucleophile / Electrophile
  • Arrows used to show the movement of 2 electrons in the reaction
  • Arrow can form or break a bond
  • Arrow can create a lone pair of electrons on a species

A simple first example is the Nucleophilic Substitution reaction of Chloromethane with Ammonia. (as seen in the equation above).

Isomers

These are new to A Level specifications and are based on the fact you can put together the atoms in an organic compound in a number of different ways from the same starting number of atoms.

So Structural Isomers have the same molecular formula but a different structural formula.

e.g. C6H12ÌýÌý can be

Hex-1-eneÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌý Hex-2-ene ÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌýÌý Cyclohexane

This is obviously not all the organic work in A Level but does give you a start and indication on some of the key areas which are new and different from GCSE.

Enjoy your A level journey and Good Luck!

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