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Is IB chemistry harder than A Level chemistry?

Chemistry is a popular and essential science for many degrees, so it’s no surprise to find many IB chemistry versus A Level chemistry discussions on the internet debating which programme is the easier route into university.

In this blog, I compare the current IB and A Level chemistry specifications (AQA, CIE, Edexcel, OCR A and Salter’s) based on content, coursework, and exam difficulty to see which really is more difficult. This is of course entirely subjective, please don’t flame me if you disagree!

Let’s start with the content:

Stoichiometric relationships (the mole, formulae and equations)

The ideal gas equation is back in all the A Level syllabuses, but IB students have more gas laws to contend with. A Level students overall get much harder mole calculations that are often set in unfamiliar contexts and are often unstructured (i.e. don’t lead you step-by-step through the calculation).

Hardest: A Level

Atomic structure

This one is close as coverage of atomic and electronic structure is the same. Except for CIE and Edexcel’s A Level, IB students learn more about the electromagnetic spectrum and emission spectra. Edexcel’s A Level also require students to draw mass spectra based on isotopic masses and abundances.

Hardest: IB


A big topic, with some big differences. Both programmes require you to thoroughly understand all the periodic trends, and exam questions are similarly difficult. A Level has significantly more inorganic chemistry content though. The IB briefly covers the alkali metals but it’s GCSE level, and entirely omits Group II metals. The halogens is also a much shorter IB topic than for A Level, which looks at reducing power of halide ions and associated redox chemistry. With transition metals, only IB students learn about the spectrochemical series, but the topic is an afterthought compared to its coverage at A Level, with all that aqueous transition metal chemistry (and colour changes!) to learn.

Hardest: A Level

Chemical bonding and structure

The content is the same in this huge topic, but the IB content gives students a deeper understanding (e.g. covering Lewis structures and formal charge) and includes demanding concepts not usually seen until degree level, including molecular orbital theory, resonance and hybridisation.

Hardest: IB


Both programmes require a good understanding of Hess’s Law, but IB students need to cope with harder, four-part energy cycles. Entropy and Gibbs energy are covered in greater depth and with more mathematical emphasis in the IB (Edexcel’s A Level comes closest). This gives IB students a much more comprehensive understanding of this topic and a greater variety of exam questions to prepare for.

Hardest: IB


There is nothing to separate them here now that Arrhenius is back in all the A Level specifications. Exam questions are of similar difficulty.

Hardest: Draw


Another topic where the IB programme gives students a more complete picture. It’s hard to judge though, because what one qualification leaves out the other includes. The IB includes reaction quotient, which helps better understand what happens when you disturb an equilibrium but omits Kp and partial pressures. Only the IB and Edexcel delve into the relationship between equilibrium and Gibbs energy though. There is little difference in exam question difficulty for students that fully grasp the concept and are adept at ICE table calculations.

Hardest: Draw

Acids and bases

This demanding, mathematical topic is much more demanding in the IB, which has more content, more depth, and more calculations, including Kb and pKb. IB students also cover pH of salt solutions and the half-equivalence point.

However, buffer calculations are now in the IB options, whereas they’re compulsory at A Level and exam questions can be very difficult and are frequently discriminating. This balances things out a lot.

Hardest: Draw


The basics (oxidation states, oxidising and reducing agents and balancing redox equations) get the same treatment in both qualifications. Rechargeable batteries and fuel cells are core to the A Level, but found only in the IB’s Energy option.

Redox titrations, another difficult area, is quite limited in the IB and based around manganese redox chemistry. A Level questions however are very demanding, with far more redox systems, unknowns to calculate, and are often unstructured, making it difficult to see how to approach the question.

What swings the balance in favour of the IB is electrochemistry, which is covered in greater depth and has more challenging exam questions.

Hardest: IB

Organic Chemistry

The current IB syllabus has less organic chemistry than the previous one, which also had the ‘Further Organic Chemistry’ option. The A Level has more organic reactions, reagents, conditions and mechanisms to learn. Both programmes require you to develop four-step synthetic routes, but A Level organic synthesis questions are more demanding and require knowledge of a much bigger reaction toolkit.

Hardest: A Level

Measurement, data processing and analysis

Both programmes have some minor content differences (IB has Index of Hydrogen Deficiency and X-ray crystallography, A Level has chromatography and high-res mass spectroscopy), but the crux of this topic is structure determination using analytical data. The ‘killer’ topic here though is NMR spectroscopy, which sees A Level students needing to know proton and carbon NMR, and face exam questions that are so difficult they make the news.

Hardest: A Level


The chemistry Internal Assessment is worth 20% of the final mark and the Extended Essay can also be chemistry-based. Choosing and executing a high-scoring IA is a challenge, but an enjoyable challenge for engaged students. It requires creativity, specialist knowledge, research skills, management skills, and communication skills.

Whereas A Level chemistry has nothing, except for CIE’s course. For the other boards, practical skills are now assessed through written exams and students get a certificate to endorse the fact they’ve done the required experiments. A Level chemistry now sadly has very little content to help student’s develop independent research skills.

Hardest: IB (no contest!)

Exam Difficulty

Mole calculations, redox, and organic chemistry are topics where A Level questions are more demanding, often due to lack of question structure and use of novel contexts to test familiar topics in unfamiliar ways. I think there is little doubt in my mind that the hardest A Level question (the totally original and creative ones designed to separate A* and A candidates) are comfortably more difficult than the hardest IB questions.

On balance however, the synoptic nature of IB exam questions, greater mathematical demand (including a multiple-choice paper where calculators can’t be used) and more demanding content in some of the most difficult areas of pre-university chemistry edges the IB in front when it comes to exam paper difficulty.

Hardest: IB (by a slim margin)

The Result

Whilst it’s a close race based on content, the slightly more difficult exam questions and coursework requirements means that, on balance the IB chemistry diploma is harder than A Level chemistry.

It also has to be noted that to earn their diploma, IB chemistry students take five other subjects (which also have demanding coursework requirements) and have to complete an Extended Essay, Theory of Knowledge essay, and undertake Creativity, Activity and Service work.

Which is better?

Despite some omissions, thanks to its excellent coursework programme, the IB overall better equips students for university-level study by giving them a broader understanding of practical chemistry and by developing essential communication and research skills. For that reason, I would say the IB Diploma offers a better pre-university education.