General Laboratory Rules

1. Permission first — Never enter the laboratory or start any experiment without permission from your teacher or laboratory technician.
2. No eating or drinking — Never eat, drink, or taste anything in the laboratory, even if you recognize a substance.
3. Work carefully — Always move carefully around the laboratory. Never run.
4. Report accidents immediately — Report all accidents to your teacher, no matter how small they seem.
5. Wash hands — Wash your hands with soap and clean water after handling chemicals.
6. Extinguish unused flames — Put out any flames not being used.

Safety Rules for Glassware

• Handle all glassware with care because it breaks easily and can cause injuries.
• Use gloves or tongs when holding glassware that has been heated.
• Never carry filled reagent bottles or volumetric flasks by their neck.

Safety Rules During Experiments

• Never point the open end of a test tube toward yourself or another person.
• Use a test tube holder when heating a test tube.
• Keep your face away from reaction vessels to avoid inhaling poisonous fumes.
• Always ensure windows are open for proper ventilation.
• Never smell a substance directly — waft the vapor toward your nose using your hand.

Rules for Handling Chemicals

• Never use chemicals that are not labeled.
• Always use a clean spatula or spoon when taking a portion of a chemical.
• Never smell chemicals directly.
• Never touch chemicals with bare hands.

Personal Protective Equipment (PPE)

1. Laboratory coat — Protects your clothes from spills and chemical splashes.
2. Safety goggles — Protects your eyes from chemical splashes and flying particles.
3. Gloves — Protects your hands when handling chemicals or hot apparatus.

Emergency Equipment Locations

• Fire extinguisher — Know its location and how to use it.
• Eyewash station — Used to rinse chemicals from eyes.
• First aid kit — Contains materials for treating minor injuries.
• Fire blanket — Used to smother small fires or wrap injured persons.

Working Safely

• Never use broken or chipped glassware.
• Turn off burners when not in use.
• Do not play with gas taps, water taps, or electrical sockets.
• Keep your workspace clean and tidy.
• Dispose of chemical waste properly according to instructions.

Laboratories use international symbols to warn users about the dangers of chemicals. These symbols are found on chemical containers.

Illustrative Case: Imagine you see a bottle in the laboratory with a skull and crossbones symbol. This tells you the chemical inside is toxic. You should not taste it, and you must wear gloves when handling it. If any spills on your skin, wash immediately with plenty of water and inform your teacher.

Burns

• Minor burns (from heat): Cool the area under running cold water for several minutes. Cover with a clean bandage.
• Chemical burns: Flush the affected area with plenty of water for at least 15 minutes. Seek medical help immediately.

Eye Injuries

• If chemicals splash into your eyes, use the eyewash station immediately. Hold your eyelids open and rinse for at least 15 minutes. Report to your teacher and seek medical attention.

Cuts from Glass

• Do not remove broken glass with your hands. Inform your teacher.
• If you get a minor cut, apply pressure with a clean cloth, wash the wound, and apply a bandage.

Swallowed Chemicals

• Do not induce vomiting unless instructed by a medical professional.
• Rinse your mouth with water and immediately seek medical help. Bring the chemical container to show the doctor.

Inhaled Fumes

• Move to fresh air immediately. Sit down and rest. If breathing difficulties continue, seek medical help.

Classes of Fire

Types of Fire Extinguishers

1. Water extinguisher — Used for Class A fires only. Never use on electrical or flammable liquid fires.
2. Foam extinguisher — Used for Class A and Class B fires.
3. Carbon dioxide (CO₂) extinguisher — Used for Class B, Class C, and Class E fires. Safe for electrical equipment.
4. Dry powder extinguisher — Can be used for multiple classes, especially Class D fires.

How to Use a Fire Extinguisher (PASS Method)

1. Pull the pin — Remove the safety pin.
2. Aim at the base of the fire — Point the nozzle at the base of the flames.
3. Squeeze the handle — Press the handle to release the extinguishing agent.
4. Sweep from side to side — Move the nozzle side to side at the base of the fire.

What To Do in Case of Fire

• Alert everyone in the laboratory immediately.
• If your clothing catches fire, stop, drop, and roll to smother the flames. Alternatively, use a fire blanket.
• For small fires, use the appropriate extinguisher following the PASS method.
• Evacuate the laboratory if the fire cannot be controlled.
• Know the location of exits and emergency assembly points.

Measuring Equipment

Heating Equipment

Holding and Supporting Apparatus

Reaction and Mixing Apparatus

Storage Apparatus

Illustrative Case: Suppose you need to prepare 100 mL of salt solution for an experiment. You would:

1. Use a measuring cylinder to measure 100 mL of water.
2. Use a spatula to add salt crystals to the water.
3. Stir with a glass rod in a beaker until dissolved.
4. Transfer to a volumetric flask if you need a precise volume.

Understanding laboratory safety and apparatus is not only important for passing chemistry exams but also for everyday life in Tanzania. For example, when you visit a pharmacy to buy cleaning products like bleach (sodium hypochlorite), you will see warning symbols on the label — the corrosive symbol reminds you to wear gloves and avoid contact with skin. Similarly, knowing how to use a fire extinguisher is a valuable skill that can help in home or market fires, where Class A fires (burning stalls or wooden structures) are common in Tanzania.