The Ultimate Guide To H3 Chemistry (A-Levels)

H3 Chemistry Guide

If you’ve done well during your promotional examinations in JC1, you may have been offered the opportunity to take H3 Chemistry as a subject in JC2.

What is H3 Chemistry like, and should you be taking it?

Here’s what you need to know.

How would I be eligible to study H3 Chemistry?

To be eligible to study H3 chemistry, you will usually need to do well for H2 Chemistry during your promotions in JC1. If you meet the criteria for H3 subjects, your school will offer you the subject.

If you were offered H3 Chemistry by your school, this means that you have done well for your H2 Chemistry during the promotional exams. You may also have to perform well in your other subjects to show that you will be able to cope with an additional H3 subject.

For example, here is what was mentioned on ACJC’s website:

ACJC H3 Criteria

You can find out more about how ACJC differs from NJC and NYJC.

In most JCs, you will be able to take up to two H3 subjects. Otherwise, you may exceed the total allowable Academic Units (12).

MOE A Level AUs

Due to this limitation, you won’t be able to take triple science in JC either.

What is the syllabus of H3 chemistry?

H3 Chemistry mainly focuses on 2 areas in chemistry: Spectroscopic Techniques and Further Organic Mechanisms. You will learn concepts that you were taught in H2 Chemistry in greater depth, such as orbital theory, spectroscopic techniques, and more advanced mechanisms (e.g. Nucleophilic Substitution and Elimination).

Here are some of the topics that you’ll learn in these 2 areas:

Further Organic
Basic Principles
of Spectroscopy
Basic Physical
Organic Chemistry
Infra-red (IR)
Nucleophilic Substitution 
Nuclear Magnetic
Resonance (NMR)
Mass Spectrometry 

You will learn the various spectroscopic techniques which will be useful if you are geared towards a lab-based profession in the future. Having this background knowledge will definitely help you to grasp these concepts more easily during university.

Although I enjoyed drawing the mechanisms in H2 Chemistry, it’s a totally different ball game for H3 Chemistry!

The mechanisms were much more ‘advanced‘. Even though the template mechanism is easy to understand, it becomes much more complicated when the compounds that react with each other are really complex.

Sometimes, it was hard to see what was required for to kickstart or continue the mechanism. As such, I really struggled for this part and took a long time before I finally understood the concepts!

What is the difference between H2 and H3 Chemistry?

The syllabus for H2 Chemistry focuses on a variety of aspects of Chemistry (e.g. Electrochemistry, Transition Elements), while H3 Chemistry mainly focuses on organic chemistry. Furthermore, the time you take to study for H3 Chemistry (1 year) is shorter compared to H2 Chemistry (2 years).

Here is a table to compare between H2 and H3 Chemistry:

H3 ChemistryH2 Chemistry
SyllabusOrganic ChemistryAll aspects of Chemistry
(e.g. Acid-Bases, Electrochemistry)
Types of
Mainly free
response questions
Multiple choice, structured and
free response questions
Merit,Pass, Fail
Counts towards
Rank Points (A-U)
of Papers
One 100
mark paper
4 papers (30m, 75m,
80m and 55m)
of years
1 (after JC1)2 (at start of JC1)
TimetableMay be outside
normal school timings
Should be within
normal school timings

While the breadth of topics that are covered in H3 Chemistry is less compared to H2 Chemistry, H3 Chemistry goes more in-depth into the topics that are taught.

Depending on how good your concepts are in these areas, you may find H3 Chemistry easy or hard!

Is H3 Chemistry difficult?

H3 Chemistry can be difficult if you do not have the time to practice the concepts outside of the normal curriculum. It will be a challenge for you if have other commitments apart from academics, such as your CCA.

Since H3 Chemistry is taught at the start of J2, it is important for you to get the fundamentals right by practising them from the start.

However, I was participating in the floorball nationals for my JC at that time, so I did not really have the time to practice the concepts outside of school.

During that period, H3 became more of a ‘chore’ for me and it was my last priority, so I did not really put much effort into it. As a result, I struggled quite a bit during the entire year as my fundamentals were weak.

As such, I would not recommend this subject if you are unable to commit extra time outside of the curriculum to practice these topics.

During the first few tutorials, I was already stumped by the topics that were being taught, and I just could not grasp the concepts well.

The mechanism drawing was really hard, and I feel that you’ll need to practice it a lot before you can understand how they work!

In terms of the paper, you will sit for a 2h 30min paper for a total of 100 marks. There are 2 different sections in the paper:

Section ASection B
60 marks40 marks
Compulsory questions2 out of 3 questions

The questions that are tested in the paper may be easier compared to the ones that are set by your chemistry teachers in JC.

However, the time can be tight, particularly if your fundamentals aren’t strong (like me). If you are unable to answer the earlier questions, you may have some problems in answering the later questions as they are all linked together!

Should I take H3 chemistry?

H3 Chemistry is suitable if you are looking to further your knowledge in organic chemistry and spectroscopy techniques, which will be useful if you are intending to take up a lab-based profession in the future.

H3 Chemistry may not be for everyone, especially since some of the topics may be abstract or ‘boring’. However, I feel that the topics will be very useful if you intend to delve into these lab techniques for your future profession.

It is definitely an added bonus if you have an interest in the topics that are being taught.

The things that I learned during H3 Chemistry were useful for some of my modules in Pharmacy, which touched on spectroscopy and pharmaceutical chemistry.

You can find out the differences between NUS Pharmacy and Pharmaceutical Science here.

One thing you may want to note is that the grade that you get in H3 Chemistry will not count into your Rank Points (RP). Instead of getting an A-U grade, you will either get a Pass, Merit or Distinction.

This is also similar to the difference in grading between H3 Maths and Further Maths.

While most local universities may only look at your Rank Points, your grade in H3 Chemistry may help to spruce up your application for an overseas university!

Nevertheless, it may still help you if you are looking to apply for any scholarships in the Chemistry field.

As such, I would recommend you to take H3 Chemistry if you are truly interested in the topics that are being taught, such as Spectroscopy and Organic Chemistry.


H3 Chemistry is one of the few H3 subjects you can take, and will be offered to you if you do well in your JC1 promotional exams.

If you feel that you can cope with the extra workload of a subject and have a strong interest in the topics, I would suggest that you go for it!

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