A free, browser-based virtual chemistry laboratory for Cambridge AS Level Chemistry (9701 Paper 3). Practice real past-paper experiments at home — no equipment needed.
Cambridge Paper 3 (Advanced Practical Skills) tests students on titrations, enthalpy experiments, and qualitative analysis — all done in a real school lab. This simulator brings those experiments to any device so students can practise the full workflow: set up apparatus, mix chemicals, record observations, write answers, and get instant mark-scheme feedback.
- 23 real past papers — Feb/Mar sessions from 2021 to 2025, covering every question type students will encounter.
- Full virtual bench — choose glassware, add reagents, heat, stir, filter, and weigh, with realistic colour changes and gas observations.
- Live reaction feedback — the lab responds to what you do: indicators change colour at the endpoint, precipitates form, gases are identified.
- Measurement precision hints — get nudged when a burette reading isn't to 0.05 cm³ or a balance reading isn't to 0.01 g.
- Per-question answer boxes — type written answers alongside each question part, mirroring the Cambridge answer booklet layout. Add results tables and scatter graphs directly within each answer box.
- Free Lab mode — experiment without a set paper; great for exploring reactions and building intuition.
- Automated marking — a built-in rubric engine scores every section against the Cambridge mark scheme and gives criterion-by-criterion feedback.
- PDF report export — download a formatted report of your session including observations, answers, and scores.
- Multilingual UI — switch between English, Tamil, Hindi, Spanish, and Chinese.
- Works offline — your session is saved automatically; nothing is lost on refresh.
- Pick a paper — choose any past paper from the Paper selector at the top.
- Read the question — the Paper tab shows the full question context and each part.
- Do the experiment — switch to the Lab tab, set up your bench, and carry out the practical.
- Write your answers — type answers into each question part box in the Paper tab. Use the inline table and graph tools to record results alongside each question.
- Submit for marking — go to the Evaluate tab and click Submit for Evaluation to see your score.
You need Node.js 20+.
git clone https://github.com/nsriram/chem_lab.git
cd chem_lab
npm install
npm run dev # opens at http://localhost:5173| Paper type | Topics |
|---|---|
| Quantitative | Rate of reaction (clock), acid-base titration, iodometric titration, back-titration, water of crystallisation |
| Energetics | Enthalpy of displacement, enthalpy of neutralisation, thermometric titration, thermal decomposition |
| Qualitative | Cation tests (NaOH, NH₃), anion tests (BaCl₂, AgNO₃, KMnO₄), gas tests, ionic equations |
Contributions are welcome! See CONTRIBUTING.md for how to get started, and DESIGN.md for how the app is built.
MIT © 2024 nsriram