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Chemistry · Chapter 1: Introduction to Chemistry
Laboratory Safety and Apparatus
Chemistry lab safety rules, hazard symbols and safety equipment, and the uses of common apparatus such as burette, pipette and Bunsen burner.
Key termRememberExampleWatch out
01Concept
A chemistry lab is safe if you follow the rules every time. Most lab accidents happen because someone was rushing, not paying attention or not wearing safety equipment.
Rules of laboratory safety
- Never enter the lab or start work without your teacher.
- Wear safety goggles and a lab coat, and tie back long hair and dupattas, especially near a flame.
- Never eat, drink or taste anything in the lab, and never smell a chemical directly. If you must smell, wave the vapour towards your nose with your hand.
- Read the label twice before using any chemical.
- Point a heated test tube away from yourself and others.
- Always add acid to water, slowly. Never add water to acid: it can boil and splash.
- Use the fume cupboard for chemicals that give off harmful gases.
- Report every accident, spill or broken glass to your teacher at once.
- Turn off the gas and clean your bench when you finish; wash your hands.
Hazard symbols
Bottles of dangerous chemicals carry hazard symbols: a black sign inside a red diamond. Learn what they mean.
| Symbol | Meaning | Example |
|---|---|---|
| Flammable | Catches fire easily | Petrol, alcohol, LPG |
| Toxic | Poisonous; can kill or harm even in small amounts | Mercury compounds |
| Corrosive | Destroys skin and metal | Concentrated sulphuric acid, caustic soda |
| Harmful / irritant | Irritates skin, eyes or lungs | Dilute ammonia, bleach |
| Oxidising | Releases oxygen and makes fires burn fiercely | Hydrogen peroxide, potassium nitrate |
Safety equipment
- Safety goggles: protect the eyes from splashes.
- Lab coat and gloves: protect skin and clothes.
- Fire extinguisher and fire blanket: put out small fires.
- Fume cupboard: removes harmful gases.
- First-aid box and eye-wash station.
Common apparatus
| Apparatus | Used for |
|---|---|
| Beaker | Holding, mixing and heating liquids (rough volumes only) |
| Conical flask | Mixing liquids by swirling without spilling; used in titration |
| Test tube | Small-scale reactions and tests |
| Measuring cylinder | Measuring the volume of a liquid fairly accurately |
| Burette | Adding a liquid drop by drop and measuring the exact volume added (titration) |
| Pipette | Transferring an exact fixed volume of liquid, e.g. 25.0 cm³ |
| Funnel | Pouring liquids; with filter paper, for filtration |
| Bunsen burner | Heating |
02Real World Examples
Gas cylinders at home
LPG is flammable. Keep cylinders upright, away from heat, and check pipes for leaks with soapy water, never a match.
Cleaning products
Toilet cleaners and drain openers are corrosive. Never mix bleach with acid cleaners: they release poisonous chlorine gas.
Medicines at home
Keep medicines and chemicals out of children's reach and in their labelled bottles: never in soft-drink bottles.
Petrol stations
The "no smoking" signs are there because petrol vapour is highly flammable.
03Practice Questions
Try to answer in your own words first, then open the model answer.
Short questions
Q1.Write any five rules of laboratory safety.Show answer
Answer
- Wear goggles and a lab coat.
- Never eat, drink or taste chemicals in the lab.
- Point a heated test tube away from people.
- Always add acid to water, never water to acid.
- Report every accident or spill to the teacher.
Q2.Why should acid be added to water and not water to acid?Show answer
Answer
Mixing acid and water gives out a lot of heat. If water is added to concentrated acid, the small amount of water can boil suddenly and splash acid out. Adding acid slowly to a large amount of water keeps it cool.
Q3.What do the flammable and corrosive symbols mean? Give one example each.Show answer
Answer
- Flammable: catches fire easily. Petrol.
- Corrosive: destroys skin and metals. Concentrated sulphuric acid.
Q4.Differentiate between a burette and a pipette.Show answer
Answer
- Burette: adds liquid drop by drop and measures any volume added, read from its scale.
- Pipette: transfers one exact fixed volume, such as 25.0 cm³.
Long questions
Q5.Describe five hazard symbols and the safety equipment found in a chemistry lab.Show answer
Answer
Hazard symbols:
- Flammable: catches fire easily (petrol).
- Toxic: poisonous (mercury compounds).
- Corrosive: destroys skin and metal (concentrated acids).
- Harmful/irritant: irritates skin and eyes (dilute ammonia).
- Oxidising: makes fires burn fiercely (hydrogen peroxide).
Safety equipment: goggles, lab coat, gloves, fire extinguisher, fire blanket, fume cupboard, first-aid box and eye-wash station.