Laboratory rules and safety measures
A chemistry laboratory has many chemicals and pieces of equipment that can cause harm if used carelessly. Safety rules protect you, your classmates and the results of your work.
| Rule | Why |
|---|---|
| Wear a laboratory coat and eye protection | Protects skin, clothes and eyes from splashes |
| Never taste, eat or drink in the laboratory | Chemicals can be poisonous |
| Tie back long hair; no loose clothing | They can catch fire or knock things over |
| Never smell a gas directly; waft it towards you | Some gases damage the nose and lungs |
| Read the label before using a chemical | You must know the hazard and the strength |
| Add acid to water, never water to acid | Mixing releases heat that can make the acid spit |
| Point test tubes away from people when heating | Hot liquids may shoot out |
| Wash your hands and clean the bench at the end | Removes traces of chemicals |
First aid
First aid is the first help given to an injured person before a nurse or doctor arrives. Tell the teacher at once about any accident.
| Accident | First aid |
|---|---|
| Acid or alkali on the skin | Wash with plenty of running water for several minutes |
| Chemical in the eye | Rinse with clean running water for at least 10 minutes and get medical help |
| Small burn | Cool under running cold water for 10 minutes; do not burst blisters |
| Cut | Press with a clean cloth to stop the bleeding; cover with a plaster |
| Swallowed a chemical | Do not make the person vomit; rinse the mouth and get medical help at once |
| Breathed in a harmful gas | Move to fresh air and get medical help |
Fire and firefighting
A fire needs three things at the same time: fuel, heat and oxygen. This is the fire triangle. A fire is put out by taking one of them away.
| Fire fighting material | Best for | Never use it on |
|---|---|---|
| Water | Wood, paper, cloth | Burning oil or electrical equipment |
| Sand | Small oil and metal fires | — |
| Fire blanket | Burning clothes, a small fire in a pan | — |
| Carbon dioxide extinguisher | Electrical and liquid fires | Burning metals |
| Foam extinguisher | Burning liquids | Electrical fires |
| Dry powder extinguisher | Most fires, including electrical | — |
Try itDiluting an acid safely
You need a dilute solution from a concentrated stock. The same amount of acid is in the stock you take and in the final solution: C₁ × V₁ = C₂ × V₂. Always add the acid slowly to the water.
Practise preparing a dilute solution from a stock solution.
Key terms
- First aid
- Immediate help given to an injured person before a nurse or doctor arrives.
- Fire triangle
- Fuel, heat and oxygen: the three things a fire needs.
- Hazard symbol
- A picture on a label that warns of a danger such as fire or poison.
- Dilution
- Making a solution weaker by adding more solvent.
Summary
- Follow laboratory rules: protect eyes and skin, never taste chemicals, add acid to water.
- Know the hazard symbols and the position of the first aid box, extinguisher and exits.
- For skin or eye contact with a chemical, wash with plenty of running water.
- A fire needs fuel, heat and oxygen; remove one to put it out, and choose the right extinguisher.