Grade 12 · Practical
Investigation: rate of reaction and factors affecting it
Prescribed investigations · about 3 min
Visual overview: Investigation: rate of reaction and factors affecting it1 MIN READ
2 study sections · pause after each one and recall the key ideaAim: to investigate how concentration, temperature and surface area affect the rate of a reaction.
Key points- Apparatus: sodium thiosulphate and hydrochloric acid (or marble chips), conical flask, stopwatch, thermometer.
- Method: change ONE variable at a time and time how long the reaction takes to reach a fixed endpoint.
- Rate is proportional to 1/time — plot 1/t against the variable.
- Control everything else: volume, total mass and temperature where not being tested.
- Independent variable — the one you deliberately change.
- Fair test — only one variable changes at a time.
EXAM TIP
explain every result with collision theory — more frequent and/or more energetic collisions.