Many of the reactions in Chemistry can be explained by reference to the bonds that exist between the relevant species, but some bonds are a bit more difficult to understand

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(Why cannot we human beings be like the lovely little creatures above!)

My underlying assumption in writing these blogs is that you have come here because you want some aspect of Chemistry explained to you. My blogs have therefore become longer in recent weeks because I am trying to explain things in greater depth. You can access my  books by going to the link “My Books” at the very top right of this webpage. Depending on what topic I am working on at the time, a Chapter in one of the two books will be updated almost every week during term time.

If you are in Year 13/the Upper Sixth, then next Autumn your life as a ‘child’ will come to an end and you will become an adult. The transition will be both daunting and at the same time exciting! During that transition you will inevitably make some mistakes (and I made many), but mistakes can be hugely helpful because if you are intelligent then you learn from your mistakes, and you then become a better person.

Here is a little trick that might help you in all your subjects (and not just in Chemistry)  –  and it will be especially valuable when you get to University or Med School/ Law School/ wherever. Create a “memory tree” for every important topic in every subject (cf. the Benzene memory tree in my Benzene blogs), and in the weeks leading up to the exams, twice a week go to bed early and spend three hours going through (in your head) every single memory tree in every single subject. The reason that some students do not get high grades is sadly NOT because they lack knowledge, but because they waste valuable time in trying to remember things that they could easily have memorised. For example, in 60 seconds can you tell me how to get from Benzene to an azo dye, and tell me ALL the reaction conditions that are needed for each of the four steps involved (and there is no thought process in this because all that it requires is recall from memory)? Now do you see what I mean! If you do not finish all the questions in an exam paper, then you just cannot get an A* or an A in the subject.

It is interesting that in 20 years of teaching ‘A’ Level Chemistry, only one of my students has gone on to read Chemistry at University, but almost all of my students have gone on to be extremely successful Doctors/Dentists/Lawyers/Engineers/etc. Chemistry as such has thus been absolutely unimportant to them! What is important is that it helped them to learn use their brains, and to demonstrate to prospective employers that they had decent brains and knew how to use them.

When you have left University/Med School/Law School/whatever, other than for having to put the details in a box on an Application form, I doubt that anyone will ever ask you what University you attended/what you read/and what Class of Degree you gained. However, what will be of interest to everybody will be how well you do your job  –  and your two years of ‘A’ Levels and your time at University will contribute hugely to that.

The Blogs

It does not matter what anyone tells you or what the newspapers might say, the post-2015 exams HAVE become much more difficult. It is not the case that the examiners expect you to know more difficult Chemistry. They are testing almost exactly the same topics in Chemistry, but they are testing them in a totally different manner. What they are doing is testing simple concepts by giving you extremely complicated looking examples that are certainly not in the Syllabus, but what they want is for you to deduce/to work out the simple principles that are contained in the examples that they give you, and then they expect you to apply those principles to come up with the answer that they want. THAT is what the modern ‘A’ Level Chemistry exam is all about!

In principle there is nothing wrong about/nothing unfair with this approach to testing the knowledge that candidates have of Chemistry. What is unfair (in my opinion) is the time allocated to do what you are required to do. In the exam you will not have the time to work out things from first principles. You can therefore help yourself greatly by committing to memory as much as you can of every topic in the Syllabus.

There are candidates who do answer the questions that are set today and get high marks in the exams, therefore there is no point in complaining about the way that the exams are run. If some people can do it in the time given, then every candidate of the appropriate calibre with the requisite knowledge is required to do so  –  so just make sure that YOU are one of the people who can do it. It is up to you to make sure that you can do what they want you to do. If you want to be an “A” grade student, then

  1. Make sure that you know the work involved in the Syllabus
  2. Make sure that you know how to apply that knowledge –  and the only way that you can do this is to do example after example after example from the textbook that your school uses/and also from Jim Clark (ISBN: 9780582411272).

Last year (2018/19) I spent more time on Second Year Blogs than on First Year ones. This year (2019/20) I may reverse that process for the reason that if you have a good understanding of  the basics of Chemistry, then the complicated stuff will be a lot easier than if your foundations are weak/are shaky.


Blogs for the week following Sunday the 29th of September 2019

‘4s’ before ‘3d’, Really?, First Year Blog 6th October 2019

Ionic Equations and Half-Equations, 6th October 2019


Previous Second Year ‘A’ Level Chemistry Blogs

A Second Chance

Acids and Bases, 23rd March 2019a

Acids and Bases, 23rd March 2019b

Benzene, Part 1, 15th December 2018

Benzene, Part 2, 22nd December 2018

Benzene, Part 3, 29th December 2018

Benzene, Part 4, 5th January 2019

Calculation of pH values during a titration (a blog for Second Year ‘A’ Level students who are just about to sit their final exams), 30th March 2019

Carbonyl Compounds, Part 1 (Acids), 12th January 2019

Carbonyl Compounds, Part 2 (Aldehydes), 19th January 2019

Carbonyl compounds, Part 3 (Ketones), 26th January 2019

Chromatography, Second Year Blog for 11th May 2019

Equivalence Points, 23rd of March 2019

Electrophoresis and DNA Fingerprinting, 18th May 2019

Entropy, Second Year Blog, 1st June 2019

Equilibrium Acid Dissociation Constant, Ka (A year 2 Blog, 15th September 2019)

Equilibrium Constants (A Summary), Year 2 Blog for the week beginning 22nd September 2019

Halides and Sulphuric Acid, Second Year Blog, 4th May 2019

IR Spectroscopy, 27th April 2019

Kc : Ka : pKa : and Kw, Strong and Weak Acids, Second Year Blog for 18th May 2019

Kw, A Second Year Blog for the week beginning 22nd September 2019

Kw equations to memorise for the exams, Year 2 Blog for 25th May 2019

Kw, The Ionic Product of Water Equilibrium constant, Year 2 Blog, 25th May 2019

Mass Spectroscopy, 20th April 2019

NMR:MRI Spectroscopy, Second Year Blog, 4th May 2019

Nucleosynthesis (posted in the Summer hols of 2019)

Participants in the development of Molecular Biology, UK 1920-1970

Potassium Permanganate and Sodium Sulphite, Three reactions, 17th November 2018

Properties of Period 3 Elements and their Oxides, 1st December 2018

Signposts for alculating pH values in acid-base titrations

Some Maths for Chemistry, A Years 1 and 2 Blog, 29th September 2019

Sulphuric Acid and Halides, 9th March 2019

The Maths in Rates of Reactions, Year 2 Blog for the week beginning 29th September 2019

Transition Metals: Complexes, 24th November 2018


Previous First Year ‘A’ Level Chemistry Blogs

Acids and Bases, 23rd of March 2019

Calculations in Chemistry, Part 1, 23rd of February 2019

Calculations in Chemistry, Part 2, 2nd of March 2019

Calculations in Chemistry, Part 3, 9th of March 2019

Calculations in Chemistry, Part 4, 16th of March 2019

Colour Changes, 8th December 2018

Consequences of Bonding and Structure

∆H of Formation, 24th November 2018

Electrophilic Addition Reactions of Ethene, 10th November 2018

Fractional Distillation and Cracking, 1st December 2018

Ionic and Molecular substances, (The difference between), 2nd of March 2019

Isomerism, Cis:Trans, 3rd November 2018

Isomerism, Structural, 27th October 2018

Mass Spectrometry, First Year Blog, 20th April 2019

Melting Points and Boiling Points, Part 1, 2nd February 2019

Melting Points and Boiling Points, Part 2, 9th February 2019

Melting Points and Boiling Points, Part 3, 16th February 2019

Melting Points and Boiling Points, Part 4, 23rd of February 2019

Some Maths for Chemistry, A Years 1 and 2 Blog, 29th September 2019

Tests, 15th December 2018

Titration (the elements of), 9th March 2019

Yield, Atom Economy or Atom Efficiency, 8th December 2018