Laboratory Techniques and Safety

Qualities of Good Laboratory

• Large windows - to allow enough light to enter in the laboratory and also for the proper ventilation.
• The door that opens outward: Allows for quick and easy exit in case of fire or other emergencies
• A supply of water for washing and cleaning the apparatus and also as a solvent to dissolve some chemicals.
• Fire extinguishers (for easy access when a fire outbreak occurs)
• A fume chamber (for carrying out experiments that produce poisonous gases or vapours)
• Storage cupboards (storing chemicals)
• Preparation room
• Rough floor to prevent a scientist from slipping.

Laboratory Rules

1. Dress properly for a laboratory activity.
1. Do not wear open-toed, backless shoes or sandals.(Wear closed shoes!)
2. Wear a laboratory coat.
3. Don’t wear short trouser
4. Wear safety goggles, to prevent the chemicals getting into your eyes.
5. Wear gloves when working with unknown chemical substances.
6. Wear breathing masks when working with a substance that releases irritating vapour eg. nitric and hydrochloric acids.
7. Waste Disposal Facilities: Proper containers for different types of waste
2. Do not enter in the laboratory without the permission.
3. Do not perform unauthorized experiments.
4. Do not taste or smell chemicals in the laboratory.
5. Do not use cracked or broken apparatus.
6. Keep inflammable substance away from naked flames.
7. Do not fight or quarrel in the laboratory.
8. Do not run in the laboratory.
9. Report any accident to the lab technician or teacher immediately it occurs.
10. Clean up any chemical spilled on the floor or working surface immediately.
11. Wash your hands thorough with plenty of water and soap after experiment.
12. Unlabelled chemicals should never be used.
13. All flammable substances must be removed before lighting a burner.
14. Replace lids, cover or stoppers after taking a chemical from containers. Never leave containers of chemicals open.

Importance of laboratory rules

• To avoid accidents when doing experiments.
• To avoid damage or breakage of apparatus and laboratory fittings.
• To ensure the accuracy and reliability of experimental results.
• To avoid wastage of laboratory chemicals.

Causes of accidents in the laboratory.

• Playing, quarreling or fighting in the laboratory.
• Improper handling of potentially dangerous chemicals.
• Poor ventilation in a laboratory may cause poisoning.
• Use of wrong reagents due to wrong labeling.
• Failure to follow right procedures for a given experiment.

Laboratory Safety Measures.

1. The laboratory should have working fire extinguishers.
2. Cupboards, storage cabinets and drawers should have locks.
3. A laboratory should have emergency exits.
4. Containers for chemicals should be checked regularly to ensure that they do not leak.
5. All chemicals should be well-labelled.

First Aid

First aid is the immediate help given to an accident victim before he/she is taken to hospital for medical help.

Importance of First Aid

1. It saves life
2. It brings hope to the victim.
3. It reduces pain.
4. It shortens recovery time.
5. Prevent permanent disability.
6. Prevents infections.

First Aid kit

First aid kit is a small box where the items necessary for first aid are kept. Components of First Aid kit

Component	Uses
Scissors/razor blade/scalpel	Used for cutting bandages, pieces of clothes.
Safety pin	Securing bandages
Bandage	Used for tying around the wound
Pain killers	Used for relieving pain eg. panadol
Soap	Used for cleaning wounds, injuries and hands during first aid.
Cotton wool	Cleaning and drying wounds.
Antiseptic solution	Cleaning wounds to kill germs

Basic Chemistry Laboratory Apparatus

Apparatus are the equipments or tools used in a laboratory to carry out experiments.

Apparatus	Uses
Dropper	Add liquid chemicals drop by drop.
Watch glass	Used to hold substance that is being weighed or observed
Tripod stand	To support apparatus which are used for heating or boiling substance.
Wire gauze	Support containers which are used for heating or boiling substance. It spreads out the flame and heat evenly (uniform distribution of heat) under the containers.
Crucible	A container in which substances can be heated to very high temperatures.
Test tube holder	Used for holding a test tube while heating
Test tube rack	Holds test tubes to prevent them from rolling
Filter funnel	Used to separate solids from liquids.
Glass rod	To mix a solution by stirring
Reagent bottle	Used to store different chemicals.
Washing bottle	Used to store distilled water.
Retort stand	Support apparatus during experiments.
Tongs	Hold hot substances and apparatus.
Separating funnel	Used to separate immiscible liquids.
Measuring syringe	For sucking in and measuring volumes of liquids or gases.
Stopwatch	To measure time during experiments.
Filter paper	Placed in a filter funnel to separate solids from liquids.
Spatula	Used for scooping small quantities of powder or crystalline chemicals.
Deflagrating spoon	Used to heat small amounts of substances inside a gas jar. Because it is longer.
Gas jar	Used for collecting gases during experiments.
Safety goggles	To protect the eyes from chemical spills, strong light and harmful vapours in the laboratory.
Thistle funnel	Used to add reagents into flasks during experiments.
Lie big condenser	It used to cool liquid vapour thereby changing it to liquid. or It is used in the distillation processes to condense vapours back into liquid.
Dessicator	It is used to dry solid chemicals.

These are some of the Laboratory apparatus

Discussion

Apparatus made of porcelain/ceramic materials:
• Mortar and pestle
• Evaporating dish
• Crucible
• Dessicators

Why porcelain materials are preferred to these apparatus

• They can withstand high temperature
• The are highly resistant to corrosion or rusting
• They do not react with most chemicals used in the laboratory.
• They can withstand mechanical stresses.
• They are easy to clean.

Why most of the laboratory apparatus are made of glass materials?

• Glass withstands high temperature.
• Glass does not react with most chemicals used in the experiments.
• Glass is transparent, this allows easy observations of the contents and processes happening inside the apparatus.
• Glass is easy to clean or wash after exeperiment.
• Glass is relatively cheaper which reduces the cost of equipping the Chemistry laboratory.

Some of the Laboratory apparatus are made of plastic materials

• They are resistant to corrosion/rusting.
• They do not react with chemicals used in experiment.
• They are less prone to breakage compared to glass.
• More affordable/ less expensive than glass.

Chemical Warning Sign

Warning signs are the symbols that alert someone to possible dangers or hazards. Chemistry is all about chemicals. Some chemicals are dangerous to the users’ health. To alert somebody for the possible danger of a certain chemical, manufacturers draw warning signs on the containers carrying those chemicals.

The chemical warning signs are labels or symbols on the containers of chemicals that alert someone to the possible dangers or hazards of the chemical inside.

1. Toxic
These are chemicals which can cause death immediately or after several days. They should not allowed to come into contact with your skin, nose or mouth.
2. Flammable
It catches fire easily eg. petrol, ethanol. They should not brought near a naked flame as they can cause explosion of fire.
3. Explosive
It can easily explode and releases small particles which can injure sensitive parts of the body eg. eyes.
4. Harmful
Poisonous when inhaled and ingested and can lead to death.
5. Irritant
It irritates the skin when in contact.
6. Corrosive
These are chemicals which can burn someone's skin immediately after contact with it.

Immediately after landing on the skin start digging through cells destroying them. Unless much water has been applied immediately, there might be a hole.

All concentrated acids and alkalis have this tendency, that is they are corrosive.

7. Oxidizing Agent (oxidant)
Chemicals which help a burning substance to burn faster. They do so as they supply oxygen to the burning substance.

Examples are potassium nitrate, potassium permanganate (VII) and hydrogen peroxide.

Exercise
In your own words briefly explain why chemicals are labelled with chemical warning signs.

Why is it important to label all chemicals and solutions clearly?

Clearly labeling all chemicals and solutions is essential to prevent accidents and ensure the accuracy of experiments. Mislabeled chemicals can lead to incorrect results, contamination, or even injuries.

Why is it essential to maintain a clean and organized workspace?

Maintaining a clean and organized workspace is crucial for preventing accidents, increasing efficiency, and ensuring accurate results.

What should you do if a chemical spills on your skin?

If a chemical spills on your skin, immediately flush the area with plenty of water for at least 15 minutes. Remove contaminated clothing and seek medical attention if necessary.

Explain the importance of knowing the location of safety equipment in a laboratory.

Knowing the location of safety equipment, such as fire extinguishers, eyewash stations, and emergency showers, is essential in case of an accident. This knowledge can help you respond quickly and effectively to emergencies.

What are the general guidelines for handling flammable materials?

Avoid using open flames near flammable substances.

Why is it crucial to read and understand experimental procedures before starting an experiment?

Reading, understanding and following the procedures correctly helps prevent mistakes and accidents.

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