Subjects
Chemistry practice, free.
Solutions, gases, the mole, equilibrium, atoms and bonding, from school and entrance exams. Every question has an explanation, and the tests are timed like the real thing.
- 170questions
- 11topics
- 3exams covered
- Freeno plans or paywalls
Chemistry in Hong Kong
Practise chemistry with the exams you can take in Hong Kong.
Where do you want to start?
- 135 questions · 6 topicsPhysical chemistryThe mole, solutions, gases, equilibrium and rates: the calculations of chemistry.Mole Calculations · States of matter · Mole concept
- 20 questions · 3 topicsAtoms and bondingAtomic structure, the periodic table and how atoms bond.Chemical Bonding · Periodic properties · Atomic Structure and Periodic Table
- 15 questions · 2 topicsOrganic chemistryCarbon compounds, their groups and reactions.Organic chemistry basics · Organic Chemistry
The most practised topics.
Each topic has its own list of questions with explanations. Pick the exam you are preparing for.
Mole Calculations
55 questions across 1 exam
States of matter
33 questions across 2 exams
Mole concept
18 questions across 2 exams
Redox and Chemical Cells
13 questions across 1 exam
Equilibrium and kinetics
10 questions across 2 exams
Organic chemistry basics
10 questions across 2 exams
Chemical Bonding
9 questions across 3 exams
Redox reactions
6 questions across 2 exams
Real questions, worked answers.
- Mole Calculations · HKDSE (Hong Kong)Find the relative formula mass of Mg(OH) 2. (H = 1, C = 12, N = 14, O = 16, Na = 23, Mg = 24, Al = 27, S = 32, Cl = 35.5, K = 39, Ca = 40, Fe = 56, Cu…See the answer and explanation →
- States of matter · Cambridge A-LevelA gas at 2 atm occupies 8 L. At constant temperature, what is its pressure (in atm) when the volume is compressed to 4 L?See the answer and explanation →
- Mole concept · Cambridge A-LevelWhat is the molar mass (in g/mol) of H 2SO 4? (H = 1, C = 12, N = 14, O = 16, Na = 23, S = 32, Ca = 40)See the answer and explanation →
Practise it for real.
Chemistry in your exam.
How to practise chemistry.
- 1
Balance the equation first
Most mole and mass questions fall apart when the equation is not balanced. Do it before any numbers.
- 2
Write the units and the formula you use
Moles, grams, litres and concentration are easy to mix up. Units on every line keep you honest.
- 3
Learn trends as patterns
Periodic trends are a few rules, not a long list. Learn why they go up or down across a period and down a group.
- 4
Do a rough check
Ask whether the answer is the right size. A negative concentration or a mass larger than you started with means a slip.
- 5
Redo your mistakes after a week
Repeat the questions you got wrong after a few days. That is when a method either sticks or fades.
Questions, answered.
- Is the chemistry practice really free?
- Yes. Every question, explanation, mock test and flashcard deck is free, with no plans or paywalls.
- Which exams does it cover?
- Chemistry questions from HKDSE (Hong Kong), Cambridge A-Level, IB Diploma. There are 170 chemistry questions on this page's list today.
- Does every question have an explanation?
- Yes. Each question has an explanation with the working or the key idea, and you can open any question on its own page.
- Can I take a timed test?
- Yes. The mock tests below run on a real timer and show a full review with explanations at the end.