Introduction
H3 Chemistry is a subject not for the faint-hearted. Whatever your motivations for taking it up are – you think H2 Chemistry is too simplistic, you want a H3 for your resume to better your university / scholarship application chances, you made it to IChO and you want to flex (lol), or you just want to challenge yourself – be prepared to encounter facets of chemistry you may never have encountered before, or have never been examined for before. Be prepared to be repeatedly confused, to struggle to complete tutorials, to be called on to present questions you have no idea how to answer – it can feel like hell at times, but with a positive learning attitude it can be quite fulfilling and you’ll learn a lot of things that can better prepare you for university-level chemistry.
Like most H3 subjects, H3 Chemistry is much more skills-based rather than content-based. That’s not to say that there isn’t much content, but mastering how to apply principles and raising your chemical intuition will get you much further than if you attempt to memorise specific mechanisms. The paper itself can test anything under the sun, so it’s impossible to spot topics or go solely off memorisation. If those are your main ways in doing well in examinations, H3 Chemistry is unlikely to suit you.
You may ask then, why take H3 Chemistry if it sounds so hard? The simple answer: passion, a love for learning, and a willingness to challenge oneself. If you love chemistry and are keen on breaking out of the confines of the H2 syllabus, then the H3 Chemistry experience is most certainly something that you will find valuable.
Syllabus
H2 Chemistry is an obvious prerequisite. Those taking H3 Chemistry are expected to be familiar with H2 concepts, so if you’re struggling to understand a significant amount of your H2 content – particularly for organic chemistry – H3 will be pretty challenging. (And that’s probably an understatement.)
There are two main parts to the syllabus: spectroscopic techniques and organic mechanisms.
The forms of spectroscopy introduced are mass spectrometry (mass spec), ultraviolet/visible-light (UV/vis) spectroscopy, infrared (IR) spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. You will also learn about basic molecular orbital theory and the quantisation of energy to help you better understand the principles behind these techniques.
For organic mechanisms, you will learn more about stereochemistry – the 3D shape of molecules, and how they give rise to more types of isomerism. You’ll learn how to assign R/S and E/Z configurations to chiral centres and double bonds respectively. There’ll be a small chapter on thermodynamics where you learn about how a reaction can produce kinetic and thermodynamic products and how to vary reaction conditions such that one product is preferentially formed. Afterwards, you’ll go more in depth into nucleophilic substitution, where you learn what factors cause SN1 or SN2 to be favoured. You will then be introduced to elimination and the E1, E2, and E1cb mechanisms, and how they compete with substitution. There’ll also be the chance to learn about more interesting things such as the Aldol and Claisen condensations and keto-enol tautomerization.
Further information is available at SEAB’s official syllabus (2022’s is linked, but the syllabus has been in place since 2019 when H3 Pharmaceutical Chemistry became H3 Chemistry).
Additional Resources
Organic Chemistry by Jonathan Clayden, Nick Greeves, and Stuart Warren is easily one of the best textbooks out there. It’s essentially a “Bible” for both H3 Chemistry and Chemistry Olympiad.
Atkins’ Physical Chemistry by Peter Atkins, Julio De Paula, and James Keeler is considered to be another “Bible” for physical chemistry, but you won’t need this as much for H3 Chemistry since there isn’t all that much physical chemistry in the syllabus. Definitely good for Olympiad students though.
Chemistry3 by Andrew Burrows, John Holman, Andrew Parsons, Gwen M Pilling, and Gareth Price is a good backup to those who are unwilling or unable to get the first two textbooks.
If digging through textbooks isn’t your style, Google is your best friend. Online resources such as Chemistry Libretexts and Wikipedia are decent for most H3 Chemistry needs.
Examination Structure
This is pretty simple: there’s only one paper with a total of 100 marks. You’ll have 2 h 30 min to attempt it, but it’s quite common for people to not complete the paper. Don’t be worried though – it’s still possible to get a distinction even with a third of the paper blank!
The H3 Chemistry paper consists of entirely free response questions, where you may be asked to write explanations, draw diagrams and mechanisms, and construct graphs from data. You will be allowed access to the Data Booklet and a calculator.
The paper is split into two sections:
Section A consists of four or five questions worth a total of 60 marks, of which you have to attempt all of them. The first question in Section A is a stimulus-based question typically worth 15 to 20 marks, where you have to answer questions based on an insert containing excerpts or summaries of actual research papers.
Section B consists of three questions each worth 20 marks, of which you choose two to attempt.
Time management is extremely important here. If you’re an average H3 Chemistry student, it’s unlikely you’ll have enough time to complete the paper, or be able to do all the questions. It’s hence necessary to be exam-smart: if you find yourself with no idea how to approach a question (e.g. you have to draw a mechanism but you have no idea how to start), just skip it and move on to something you’re more likely to get marks for. The marks you sacrifice should ideally be those that you feel are beyond your ability to get.
Another tip: try to scan through Section B when you’re checking the paper so you spend less time choosing between them during the paper. Don’t simply pick the first two because they’re the first two you come across – the last question can be and often is the easiest of the three.
Contributed by Keane Ng (RI’20)
A for H2 Chemistry; Distinction for H3 Chemistry in the 2020 A Levels
Raffles Academy for Chemistry