How to Prepare for the New IB Chemistry Exams

With just under a year left until the May 2025 IB exams, many students are noticing the need to consolidate what they have learnt in IB Chemistry up to this point.

The prospect of being the first cohort to sit the exam for the new Chemistry syllabus may seem daunting. After all, some changes are difficult to follow, and confusion arises as to which revision resources are suitable and how to work with past paper questions in revision when all of them were designed for the previous syllabus.

Summer could be a good time to refresh your chemistry knowledge before having a go at the more advanced content that awaits in the classroom from September onwards, as well as work on your IA, whatever stage it is at.

This article aims to summarise the key changes to assessment and subject content, as well as provide advice on how to use revision resources and past papers from the old syllabus to prepare for exams from 2025 onwards.

What is the New Assessment Structure?

Changes to how the course is assessed are the most noticeable feature of the new syllabus. External assessment still includes three papers, this time called Paper 1A, 1B and 2. Paper 1A does not substantially differ from the old Paper 1 and consists of 30 or 40 multiple-choice questions for SL and HL respectively.

You can now use a calculator and the data booklet to answer those questions, which will be a welcome change for many. This will likely make certain well-established question types obsolete (more about this later).

Paper 1B has essentially replaced the old Section A from Paper 3, but its weighting has increased substantially. This would signal that data analysis skills and applying knowledge in an unfamiliar context have become more important than ever before in IB Chemistry.

Paper 2 seems to remain mostly unchanged in terms of structure and the number of marks available, with a slightly increased duration at both levels. As before, it is by far the largest single component of assessment and the most challenging one for many, especially in terms of exam technique and completing all questions in good time.

See the summary of assessment below for details:

Changes to the Scientific Investigation

The way internal assessment is completed has seen several important changes as well, most of which seem to introduce more flexibility and clarity into the process. The number of assessment criteria has been reduced from six to four while maintaining the maximum number of marks at 24.

Despite these changes, no entirely new criteria have been added – it appears to be more about the old criteria being combined into a shorter list. There is now a clear word limit of 3,000 words (excluding charts, diagrams, tables, graphs, formulae, calculations/equations, references, bibliography and headers) as opposed to the ambiguous page limit from the previous syllabus.

Collaborative work is now allowed in groups of up to three students: data collection can be performed collaboratively while each student must complete their report individually. This could involve students manipulating different variables with assistance from other group members or completing a data-based investigation from a dataset previously collected as part of a larger school-wide effort.

Changes to Content

The new syllabus has been significantly re-organised, shifting away from the traditional modular approach to a ‘concept-based approach’. The syllabus is meant to focus on two essential skills - structure and reactivity, which affect each other, and students are supposed to build their understanding of chemistry based on this general idea.

This new approach based on making connections between topics is supposed to lead to a more holistic and in-depth understanding of the topics. A clear downside is that this new approach makes it difficult to identify what exactly you are struggling with since you are expected to learn multiple new concepts in unison.

It is even harder to identify which ‘old’ topic corresponds to a particular topic from the current syllabus when you’re searching for past paper questions. The table below shows all new syllabus points matched to their ‘old’ equivalents.

5 Key Changes

Several detailed summaries of the changes to the syllabus have been published to date. I would encourage everyone to read them and use them regularly as a checklist when in doubt while revising a particular topic. A shorter summary of key changes can be found below:

1. Big changes to organic chemistry – nitriles and arenes, reduction reactions, preparation of phenylamine from nitrobenzene, synthesis and retrosynthesis, polarimetry, conformational and configurational isomerism, E/Z nomenclature for alkenes, protic/aprotic solvents, and esterification have all been removed from the syllabus.
2.  Mass spectroscopy, IR spectroscopy and NMR spectroscopy are still covered at both levels, but structure identification using these techniques is only required at HL.
3.  Both synthetic and natural polymers are now part of the core syllabus.
4. The syllabus places greater emphasis on fossil fuels and alternatives – biofuels, fuel cells, and renewable and non-renewable energy are now included in the syllabus.
5. More focus on the link between Gibbs free energy and equilibria with a more detailed discussion of the reaction quotient.

What To Expect From Papers 1A and 1B

As mentioned above, it appears that Paper 1A is largely unaffected when it comes to question format, except for two main question types: calculations and questions related to trends in the periodic table. You can find two examples below, showing how a question is likely to evolve from the previous syllabus to the current one.

 Questions requiring students to select a correct calculation method rather than a numerical answer were common and challenging for candidates in previous years. They existed to accommodate the lack of calculators in the old paper 1 and will most likely be replaced with questions asking for a numerical answer instead. 

Access to the full data booklet as opposed to only the periodic table means that many questions about periodic trends have now become obsolete. Since asking to order or identify a species with the smallest or largest ionic radius/first ionisation energy makes little sense where values are listed in the data booklet, exam questions will most likely evolve to ask about quantities not listed in the booklet, such as second ionisation energy or ionic radii to test understanding of the factors behind these trends.

This is by no means an exhaustive list, but it serves to illustrate the type of questions that will need to be modified due to changes in assessment. I would still encourage students to use old paper 1 questions for practice and avoid the temptation to answer some of the questions simply by looking up values in the data booklet.

As for calculation questions, finding a numerical value is usually easier than picking the correct calculation, so these questions remain a useful way to practise spotting errors and misconceptions in many types of calculations.

Paper 1B appears to be a major challenge for most students since it requires a lot of practical knowledge as well as thinking about unfamiliar experiments and applying course knowledge in an unfamiliar context. Old paper 3 questions (section A only) can serve as useful practice material.

What To Expect From Paper 2

It is difficult to predict how exactly Paper 2 might be affected. The specimen paper does not seem to suggest any groundbreaking changes, but more emphasis on questions combining multiple topics should be expected bearing in mind the general principle behind this new syllabus.

However, the changes to the subject content itself will likely be more pronounced here than in any other assessment component. My advice would be to check the syllabus or one of the summaries of changes if anything looks completely unfamiliar.

It is also important to remember that the data booklet has been updated too – some values used in calculations as well as section numbers have changed, and students may get ‘incorrect’ numerical answers despite following the correct method. This is especially relevant to energetics calculations, now found in Reactivity 1. If that were to happen, there is no need to worry about the answer being slightly off if the calculation method is applied correctly.

Care needs to be taken when attempting any organic chemistry questions in paper 2. The removal of organic synthesis from the syllabus means that questions related to multi-step synthesis are no longer relevant even if all or most reactions required are still covered in the new syllabus.

More ‘Cosmetic’ Changes to Mark Schemes

Some cosmetic changes to how mark schemes view certain answers are also expected. It is impossible to predict what exactly they might involve, but the subject guide shows a few examples. Reaction profiles could be drawn with the x-axis labelled as any of ‘reaction progress’, ‘progress of reaction’ or ‘reaction coordinate’.

The new syllabus clearly states that the last option is the only one considered correct now. A similar cosmetic change will affect the free radical substitution mechanism. Homolytic fission of a bond never had to be shown using fish hook arrows until now but is required according to the new guide.

Small and arbitrary changes like these are bound to happen with every new syllabus. They can be a source of stress and confusion for students, but they can be mitigated by taking time to skim through the subject guide to make sure you are familiar with all points from a given unit.

Key Takeaways

1. Assessment structure has changed quite a bit, probably for the better, but past paper questions are still an excellent way to prepare for your chemistry exams, especially for Papers 1A and 1B.
2. Internal assessment criteria remain very similar despite a reshuffle, so you can still use older resources.
3. Content changes have mainly affected organic chemistry and a lot of content has been removed, making it easier to revise this notoriously difficult topic.
4. Watch out for Paper 2 questions – you may get ‘incorrect’ answers only due to changes in the data booklet.
5. The new IB Chemistry subject guide should be your main point of reference when in doubt.

Bibliography

Diploma Programme Chemistry guide, International Baccalaureate Organisation (UK) Ltd, Cardiff, 2023.

Diploma Programme Chemistry guide, International Baccalaureate Organisation (UK) Ltd, Cardiff, 2014.

chemistrytutor.me, https://chemistrytutor.me (accessed June 2024)