Should I Choose HSC Chemistry? A Practical Year 10 Guide

You heat a strip of magnesium and end up with a white solid that weighs more than the magnesium you started with. That seems wrong. If mass is conserved, where did the extra mass come from?

Make a prediction before reading on. The answer is that magnesium has reacted with oxygen from the air:

\[
\ce{2Mg + O2 -> 2MgO}
\]

The extra mass was never created. Oxygen entered the reaction from somewhere you couldn’t easily see. HSC Chemistry is full of problems like this. You observe something at the human scale, imagine what atoms and molecules must be doing, then use equations and measurements to test whether your explanation makes sense.

That is a much better way to decide whether to choose Chemistry than asking, “Am I a science person?” The real decision is whether you like this combination of reasoning, calculations, invisible particle models, practical work, and fairly precise scientific writing.

01First, know which Chemistry course you would actually be choosing

If you’re in Year 10 in NSW in 2026, you would normally begin Year 11 in 2027. That matters because there is a syllabus change coming.

The new Chemistry 11-12 Syllabus begins with Year 11 in 2028. Students beginning Year 11 in 2027 will still study the current Chemistry Stage 6 Syllabus (2017), including when they progress into Year 12. (NSW Government)

Under that syllabus, Chemistry is a 2-unit Board Developed Course. NESA lists no formal prerequisite or corequisite for Year 11 Chemistry. Your school, however, may give its own subject-selection advice based on Year 10 Science or Mathematics results. (NSW Government)

The course looks like this:

Year 12 then moves into equilibrium, acids and bases, organic chemistry, and chemical analysis. (NSW Government)

There is also substantially more investigation than students sometimes expect. The current course requires at least 35 hours of practical investigations in each year, and 15 hours of course time are allocated to depth studies. (NSW Government)

So Chemistry is not simply “learn facts about the periodic table and sit tests”.

02What does studying Chemistry actually feel like?

Imagine you dissolve salt in water.

At first, you can describe what you see: the crystals disappear.

Chemistry asks you to go further. The salt hasn’t vanished. You need to picture charged particles separating and becoming surrounded by water molecules. Then you might calculate how much salt was dissolved, predict what happens if more is added, design an experiment, analyse measurements, and explain the result using correct chemical language.

That movement between different levels is one of the defining features of the subject:

observation -> particles -> symbols -> mathematics -> explanation

A useful analogy is translating between languages. The experiment might say, “a colourless gas formed”. The particle model describes what the molecules did. The chemical equation expresses the same event using symbols. A calculation tells you how much should happen.

The analogy breaks because these aren’t simply different words for exactly the same thing. Each representation reveals information the others may hide.

Students who enjoy switching between those views often enjoy Chemistry.

Students who want every topic to stay entirely concrete can find it frustrating.

03How much maths is there?

Chemistry isn’t Mathematics Extension 2 wearing a lab coat.

But it also isn’t maths-free.

A student might hear that Chemistry has “less maths than Physics” and conclude that calculations barely matter. That’s misleading. The mathematics itself is usually not extraordinarily advanced, but you need to use relatively simple mathematics accurately and repeatedly.

You should be reasonably comfortable with algebra, ratios, scientific notation, graphs, units, percentages, and rearranging formulas.

The important word is comfortable, not perfect.

Consider a simple example.

04The calculations become more involved

Later, Chemistry often asks you to connect several small ideas rather than perform one difficult mathematical operation.

Suppose 5.85 g of sodium chloride is dissolved to make 500 mL of solution. The molar mass of sodium chloride is \(58.5\text{ g mol}^{-1}\). What is its concentration?

This is closer to the sort of multi-step thinking you need to become comfortable with.

05“I’m not great at maths.” Does that mean I shouldn’t choose Chemistry?

Not automatically.

There is a large difference between these two situations:

“I sometimes make mistakes with algebra, but I can understand it once someone explains it.”

and

“I strongly dislike calculations, avoid them whenever possible, and don’t want to practise them.”

The first student can absolutely develop the skills Chemistry requires.

The second student should think more carefully about whether the subject’s day-to-day work suits them.

Chemistry calculations also become cumulative. If basic mole calculations never become secure, later work involving concentration, stoichiometry, acids, equilibrium, and chemical analysis becomes much harder.

So the question isn’t whether you’re already brilliant at maths. It is whether you’re prepared to fix gaps rather than carrying them for two years.

If you’re also deciding which senior mathematics course to take, our guide to Maths Extension 1 vs Extension 2 explains what actually changes between those courses.

06You also need to explain things, not just calculate them

Students sometimes expect Chemistry to reward short factual answers such as:

“Temperature increases the reaction rate.”

That may be correct, but it isn’t yet much of an explanation.

You might instead need to connect the observation to collision theory: increasing temperature raises the average kinetic energy of particles, leading to more frequent collisions and a greater proportion of collisions with sufficient energy to react.

There is a chain:

change -> particle behaviour -> consequence -> observed result

That means English skills matter too.

You don’t need beautiful creative writing. You do need to read questions carefully, distinguish words such as describe, explain, and evaluate, use evidence appropriately, and write logically.

NESA’s assessment requirements give substantial weight to Working Scientifically skills as well as knowledge and understanding. For Year 11 under the current syllabus, the mandated component weightings are 60% Working Scientifically skills and 40% knowledge and understanding. Schools decide the particular tasks used to assess those components. (NSW Government)

So being able to memorise notes is useful, but insufficient.

07What about practical experiments?

You don’t have to be the person who desperately wants to wear safety glasses and own seventeen test tubes.

But you should be willing to learn from experiments.

In Chemistry, practical work isn’t separate from the theory. Suppose a reaction unexpectedly produces half the amount of product your calculation predicted. You might need to ask whether the reaction was incomplete, some product was lost during transfer, the measurement was inaccurate, or your original model was wrong.

That is scientific reasoning.

A practical task may involve deciding what to measure, controlling variables, recording data, calculating uncertainty, identifying limitations, and explaining whether the evidence actually supports a conclusion.

If your favourite part of Year 10 Science is simply watching the teacher make something change colour, HSC practical work may feel different. You’re increasingly expected to understand why the experiment was designed that way and what the measurements mean.

08A short self-check before you choose Chemistry

Don’t give yourself points. There is no useful “Chemistry personality score”. Instead, answer these questions as concretely as possible.

• When a result doesn’t make sense, do you usually want to work out why, or do you mainly want the correct answer so you can move on?
• Can you rearrange a basic formula, work with ratios, convert units, and read a graph, even if you sometimes need revision?
• Are you willing to learn symbols such as \(\mathrm{Na}^{+}\), \(\ce{SO4^2-}\), and \(\ce{H2SO4}\) until they stop looking like alphabet soup?
• Do you prefer understanding a mechanism or pattern over memorising isolated facts?
• Can you keep revising earlier topics after the class has moved on?
• Are you prepared to explain experimental results and evaluate evidence rather than just perform calculations?
• Is Chemistry useful for a university course you’re seriously considering, or are you selecting it because someone told you it “looks good”?
• Have you looked at an actual Year 11 Chemistry question rather than judging the course from Year 10 Science alone?

A few “no” answers aren’t a problem.

The more important issue is which questions produced a no.

“I haven’t learned the maths yet” can be fixed.

“I dislike practically every activity the course is built around” is a more meaningful warning.

09Who is likely to enjoy Chemistry?

Chemistry often suits students who like finding hidden explanations for visible events.

Why does rust form? Why does increasing temperature change reaction rate? Why can two substances containing similar atoms behave completely differently? How can a chemist determine the concentration of an unknown solution?

There is usually a system underneath the observation.

If you like finding that system, Chemistry can be satisfying.

It can also suit students who enjoy a mixture rather than one dominant mode of learning. A typical stretch of the course may contain theory, equations, calculations, graphs, experimental data, practical work, and written explanations.

The trade-off is that you can’t simply lean on your strongest skill forever. A student who is excellent at maths still has to explain chemistry. A student with strong memory still has to solve unfamiliar problems.

10Who might find Chemistry difficult?

One tempting misconception is that Chemistry is mostly memorisation.

There is material to remember: terminology, reaction patterns, formulas, structures, and experimental techniques.

But memorisation without understanding becomes fragile very quickly.

Imagine learning that ionic compounds often have high melting points. You could memorise the sentence. A stronger Chemistry student asks what an ionic solid looks like at the particle level, what forces must be overcome to melt it, and how that structure explains the property.

That deeper model lets you answer unfamiliar questions rather than waiting for a question you’ve already seen.

Chemistry may therefore be a poor fit if you strongly prefer subjects where you can learn a fixed response and reproduce it with little adaptation.

It may also become difficult if you regularly postpone small misunderstandings. Chemistry has an annoying habit of bringing old ideas back. Moles don’t politely disappear once Module 2 finishes.

11How heavy is the workload?

There isn’t one universal answer because schools organise lessons, homework, depth studies, and assessment tasks differently.

The official course is 120 indicative hours in Year 11, with practical investigations and depth-study requirements built into those hours. (NSW Government)

The more useful question is what happens outside class.

Chemistry tends to punish irregular study more than steady study. Ten minutes spent fixing a mole-conversion mistake when you first notice it can be more useful than rereading an entire chapter three weeks later.

You will probably need time for calculation practice, revising accumulated content, completing practical or research work, learning chemical language, and correcting mistakes from past questions.

Ask your school’s Chemistry teacher what students at your school actually complete. The specific assessment program is set by the school, so somebody else’s timetable isn’t necessarily yours. (NSW Government)

12Do you need Chemistry for university?

Sometimes Chemistry is helpful because later university subjects assume you already understand it. Sometimes it isn’t required at all.

Those are not the same thing.

A prerequisite is something you must satisfy for entry. Assumed knowledge means a university expects that background but may still admit you without it.

Requirements differ between universities, degrees, and years, so don’t choose Chemistry based on a vague statement such as “you need it for medicine” or “all science degrees require it”.

For example, the University of Sydney currently describes HSC Chemistry knowledge as assumed background for some first-year Chemistry units, while also providing other introductory pathways for students without that background. (The University of Sydney)

The practical decision rule is simple: if you already have a few possible university degrees in mind, check the current course page for each degree and look specifically for subject prerequisites, assumed knowledge, and bridging options.

Do this again in Year 12 because university requirements can change.

13Should you choose Chemistry just because of ATAR scaling?

That is a weak reason on its own.

You are choosing a course you will study for roughly two years, not buying a magical ATAR coupon.

Whatever you’ve heard about scaling, you still need to perform in the actual subject. A course that fits your interests, preparation, and working style gives you something useful to work with. A course selected purely because someone called it a “good scaling subject” may leave you spending two years fighting material you never wanted to study.

Scaling can be one piece of information. It shouldn’t substitute for course fit.

14Chemistry or Physics?

Students often consider both because they share calculations, models, experiments, and scientific reasoning. But the flavour is different.

Chemistry spends much of its time asking what matter is made of, how particles interact, why substances react, and how quantities of chemicals are measured.

Physics more often builds mathematical models of motion, forces, fields, waves, electricity, and other physical systems.

Neither description tells you which one you should choose.

A useful test is to compare real problems. Does calculating why a projectile moves a certain way sound more interesting, or explaining why a reaction proceeds and calculating how much product forms?

If Physics is also on your subject-selection sheet, read Should I Choose HSC Physics? A Practical Year 10 Guide and compare the actual work rather than the reputation of each subject.

15What if I’m only average at Year 10 Science?

Year 10 performance is useful evidence. It isn’t destiny.

Look more closely at why you’re getting your current marks.

If you lose marks because you don’t revise, make arithmetic errors, rush through graphs, or write explanations that are too vague, those are identifiable problems.

If you understand scientific explanations once they’re properly taught and you’re willing to practise, there is room to improve.

On the other hand, don’t ignore consistent difficulty and assume Year 11 will somehow reset everything. Senior Chemistry moves faster and expects greater independence.

The sensible response isn’t “I’m bad at Chemistry”.

It is something more specific, such as:

“I struggle to rearrange formulas.”

“I don’t understand ions.”

“I can calculate answers but can’t explain them.”

“I forget content after assessments.”

Specific weaknesses give you something to repair before Year 11 begins.

16Try this before submitting your subject choices

Get one genuine Year 11 Chemistry exercise from your school, teacher, or the current syllabus materials.

Spend about 20 minutes on it without worrying about your mark.

Pay attention to what happens in your head.

If you encounter unfamiliar notation and think, “I don’t know this yet, but I want to understand how it works”, that tells you something.

If every calculation, particle model, experiment, and explanation feels like work you actively don’t want to be doing for two years, that tells you something too.

Then ask your prospective Chemistry teacher three practical questions: what mathematical preparation they expect, what the Year 11 assessment program looks like at your school, and what students usually find hardest in Term 1.

The decision is not whether Chemistry is a “good subject”. It is whether its particular way of thinking is a good use of your two units.

The next useful step is to compare that answer against the other subjects competing for the same space in your timetable, using actual syllabus content and sample work rather than reputation.