Why lab safety comes first
A chemistry lab has real hazards — hot glassware, acids, flames, sharp broken glass. Almost every safety rule below exists to prevent one specific kind of accident, so instead of memorising a list, think of each rule as "what could go wrong if I didn't do this?"
Before You Touch Anything
Read and understand the instructions first, before starting any experiment. Most lab accidents happen because someone started before knowing what came next.
Personal Protective Equipment (PPE)
Always wear:
- Safety goggles — protect your eyes from splashes or debris.
- A lab coat — protects your clothes and skin.
- Gloves — protect your hands from chemicals.
Open-toed shoes are never acceptable in a chemistry lab — they leave your feet exposed to spills and broken glass.
Handling Chemicals Safely
- Never smell or taste a chemical directly to identify it.
- Diluting acid: always add acid to water, never water to acid. This one is a classic exam question. Mixing acid with water releases a lot of heat (it's exothermic). If you add water to a small amount of concentrated acid, that heat can flash the water into steam instantly, causing dangerous splattering. Adding acid slowly into a larger volume of water spreads the heat out safely.
- Chemical spill on skin: wash immediately with plenty of water — don't wait, and don't just wipe it.
Handling Heat and Flames
- Lighting a Bunsen burner: light it with a striker while keeping the airhole adjusted — never turn the gas on fully before lighting it.
- Heating a test tube: always point the open end away from yourself and everyone else, in case the contents suddenly spurt out.
Cleanup and Disposal
- Broken glassware goes into a designated sharps container — never the regular trash, and never pick it up with bare hands.
- Laboratory waste must be separated according to chemical type, not thrown together.
- Wash your hands and arms before leaving the lab, to remove any chemical residue and avoid accidentally ingesting or spreading it later.
When You're Unsure
If you don't understand a step mid-experiment, ask the instructor or supervisor — never guess, and never just skip the step.
Why a Fume Hood Matters
A fume hood (fume cupboard) exists to remove and contain hazardous fumes, vapours, and gases — not to keep out dust or store equipment.
Choosing the Right Apparatus
Different tools measure volume with different levels of precision:
- Beaker — rough, approximate volumes.
- Volumetric flask — a single, very precise volume (e.g. exactly 250 cm³ or 1 dm³).
- Burette — precise, adjustable volumes, used for titrations.
Why This Matters for Your Exams
Most safety questions describe a scenario ("a student wants to dilute acid…", "there's a chemical spill…") and ask what the correct action is. If you understand why each rule exists (not just that it exists), you can reason out the right answer even for a scenario you haven't seen before.