Which gas makes up the largest part of dry air by volume?
Based on: DSE Chem Compulsory I(a) The atmosphere
HKDSE Chemistry · HKDSE Chemistry
Free HKDSE Chemistry practice questions (all twelve compulsory topics and all three electives)
Fifteen multiple-choice questions, one from each of the twelve compulsory topics and each of the three electives, so one sitting tells you which topic is weakest rather than just how many you got right. Every question is original, written to the topic framework in the Curriculum and Assessment Guide, with an explanation and a topic reference under each. The full topic framework is on the HKDSE Chemistry topics page; the full bank of 710 questions, the flashcards and the topic notes, in English, Traditional and Simplified Chinese, are in the revision app.
Practice
Free practice questions
Which subatomic particle has a relative mass of about 1/1840?
Based on: DSE Chem Compulsory II(a) Atomic structure
Which metal is most likely to be found in the Earth's crust as the uncombined element?
Based on: DSE Chem Compulsory III(a) Occurrence and extraction of metals
Which particle does an acid produce when it dissolves in water?
Based on: DSE Chem Compulsory IV(a) Introduction to acids and alkalis
Which gas makes up the largest part of natural gas?
Based on: DSE Chem Compulsory V(a) Hydrocarbons from fossil fuels
What makes a covalent bond polar?
Based on: DSE Chem Compulsory VI(a) Polarity of bond and molecule
What is the key difference between a primary cell and a secondary cell?
Based on: DSE Chem Compulsory VII(a) Chemical cells in daily life
An exothermic reaction is carried out in an open beaker. What happens to the temperature of the reaction mixture?
Based on: DSE Chem Compulsory VIII(a) Energy changes in chemical reactions
What does the rate of a chemical reaction measure?
Based on: DSE Chem Compulsory IX(a) Rate of chemical reaction
A reversible reaction in a sealed container has reached dynamic equilibrium. Which statement is correct?
Based on: DSE Chem Compulsory X(a) Dynamic equilibrium
What do neighbouring members of a homologous series always differ by?
Based on: DSE Chem Compulsory XI(a) Introduction to selected homologous series
Which element in Period 3 has the highest melting point?
Based on: DSE Chem Compulsory XII(a) Periodic variation in physical properties of the elements from Li to Ar
The forward reaction in the Haber process is exothermic, yet the reactor is kept at about 450 °C. What is the main reason for working at such a high temperature?
Based on: DSE Chem Elective XIII(a) Importance of industrial processes
Natural rubber is the polymer of which monomer?
Based on: DSE Chem Elective XIV(a) Naturally occurring polymers
A solid gives a lilac flame in a flame test. Which metal ion does it contain?
Based on: DSE Chem Elective XV(a) Detecting the presence of chemical species
How to use fifteen questions properly
Not as a score. One question per topic is far too few to tell you how good you are at Chemistry and exactly enough to tell you where to look next. Read it as a map: the topic you miss, or get right for the wrong reason, is the topic to open first. That is why the questions are spread one per topic rather than concentrated on the compulsory part, even though the compulsory part is twelve fifteenths of the syllabus.
Read the explanation even when you were right
In Chemistry the distractors are rarely random. They are the specific confusion the topic produces: the strong acid mistaken for the concentrated one, the equilibrium read as a stopped reaction, the enthalpy change read off the activation barrier. The explanation under each question says why each wrong option is wrong, so getting the right answer for the wrong reason does not survive the page. Every question in the app is written the same way.
Equations and the arithmetic you actually need
Multiple-choice in Chemistry rewards the step before the arithmetic: the balanced equation, the mole ratio, which species is oxidised. Get those right and the number usually falls out in one line. That is the shape of the questions here and in the app, which is honest about what a four-option question can test: it will catch a mole ratio taken from the wrong side of an equation, and it will not mark a titration calculation written out over half a page. That part still belongs to your exercise book and your teacher.
The English terminology problem, stated plainly
Many Hong Kong candidates understand Chemistry in Chinese and answer in English. That is a naming problem rather than a comprehension one, and revising harder does not fix it. The questions on this page are in English because the paper is; in the app the same question, the same explanation and the same flashcard switch between English, Traditional Chinese and Simplified Chinese at a tap, so you can settle the concept in the language you think in and then check the term you will have to write.
What this page will not tell you
How many questions Paper 1 Section A has, how long the papers run or how the marks are split. Those are not stated because they are not verified against a current official document, and the assessment framework fixes the weighting rather than a count. Confirm the assessment framework with the HKEAA and with your school. What this page does state, the fifteen topics and what sits inside each, comes from the published Curriculum and Assessment Guide.
Not affiliated with the HKEAA or the EDB
RiverMap Learning is not affiliated with, endorsed by or sponsored by the Hong Kong Examinations and Assessment Authority, the Education Bureau or the Curriculum Development Council. Every question here is original and written to the published topic framework; no past paper question, marking scheme or textbook content is reproduced. Practice results are not a grade.
| Compulsory part | Elective part | |
|---|---|---|
| How many topics | Twelve | Three exist, each school enters candidates for two |
| Who studies it | Every candidate | Depends on the school's pairing |
| What it covers | Planet Earth through to patterns in the chemical world | Industrial, materials and analytical chemistry |
| Relationship | The base every elective builds on | One compulsory strand taken further |
| In our question bank | All twelve | All three, so a change of pairing costs you nothing |
FAQ
Frequently asked questions
How many free HKDSE Chemistry questions are on this page?
Fifteen, one from each topic: the twelve compulsory topics from Planet Earth through to Patterns in the Chemical World, plus Industrial Chemistry, Materials Chemistry and Analytical Chemistry. Each carries an explanation and the topic it maps to. The full bank of 710 questions is in the app.
Are these real HKDSE Chemistry past paper questions?
No, and deliberately not. Every question is written from scratch by RiverMap Learning to the topic framework in the publicly available Chemistry Curriculum and Assessment Guide. No HKEAA past paper question, marking scheme or textbook content is reproduced. Scientific facts are not copyrightable; the published framework is used only to align coverage.
How many elective units of HKDSE Chemistry do you have to study?
Two of the three. The electives are Industrial Chemistry, Materials Chemistry and Analytical Chemistry, and a school normally enters its candidates for two of them. Which two is the school's decision rather than the candidate's, which is why our bank carries all three.
How many multiple-choice questions are in HKDSE Chemistry Paper 1 Section A?
This page does not state a number. The assessment framework fixes the weighting of Section A, not a question count, so figures quoted online are usually one year's actual paper rather than a rule that binds the next sitting. Check the framework published by the HKEAA and confirm with your school.
Are the questions in English or Chinese?
The questions on this page are in English, because the English paper is what most candidates sit. In the app every question, option, explanation, flashcard and topic note exists in English, Traditional Chinese and Simplified Chinese, switching at a tap, so you can work out the chemistry in the language you think in and then check the term you will have to write.
Does a good score here mean you will do well in the real exam?
No. Fifteen questions is a diagnostic, not a prediction, and there is no pass mark on this page or in the app because HKDSE levels are awarded by standards-referenced reporting each year rather than against a fixed mark. Use the result to pick which topic to open next.