LABORATORY FAMILIARIZATION

STEP 1: MEANING OF A CHEMISTRY LABORATORY

A laboratory is a specially designed place where scientific investigations, experiments, measurements and observations are carried out.

A chemistry laboratory contains equipment and materials that allow scientists and students to study substances safely.

Laboratory work is important because chemistry is both theoretical and practical. We do not only learn what substances do; we can also investigate their properties experimentally.

STEP 2: COMMON LABORATORY APPARATUS

Test Tube

A test tube is a small glass or plastic container used for holding, mixing or heating small quantities of substances.

Beaker

A beaker is a cylindrical container, usually made of glass, used for holding, mixing and heating liquids.

A beaker can provide approximate volume measurements, but it is not normally used when a highly accurate volume is required.

Conical Flask

A conical flask has a broad bottom and narrow neck.

It is useful for mixing liquids because its shape makes it less likely for the liquid to splash out.

Measuring Cylinder

A measuring cylinder is used to measure liquid volume more accurately than a beaker.

Its graduations allow the volume of a liquid to be read.

Burette

A burette is a long graduated tube fitted with a tap.

It is used to deliver measured volumes of liquids, especially during titration.

Pipette

A pipette is used to transfer a measured volume of liquid accurately.

Funnel

A funnel is used to transfer liquids into containers with narrow openings. With filter paper, it can also be used for filtration.

Evaporating Dish

An evaporating dish is used to evaporate a solvent from a solution.

Crucible

A crucible is a small heat-resistant container used for strongly heating substances.

Tripod Stand

A tripod is a three-legged support used to hold apparatus above a heat source.

Wire Gauze

Wire gauze is placed on a tripod or other support to provide a stable surface for a container during heating and to distribute heat.

Bunsen Burner

A Bunsen burner is a laboratory heating device that uses gas to produce a flame.

Thermometer

A thermometer is used to measure temperature.

Balance

A laboratory balance is used to determine the mass of a substance.

Spatula

A spatula is used to transfer small quantities of solid chemicals.

Glass Rod

A glass rod is commonly used for stirring and for guiding liquids during pouring.

STEP 3: IMPORTANT LABORATORY SAFETY RULES

The chemistry laboratory contains substances and equipment that may cause injury if handled carelessly.

Students should therefore:

1. Wear appropriate protective clothing when required.

2.Never taste chemicals.

3.Never directly smell an unknown chemical.

4.Never point a heated test tube toward yourself or another person.

5.Never perform an experiment without understanding the instructions.

6.Keep the laboratory clean and dry.

Report spills and accidents immediately.

7.Use the correct apparatus for each experiment.

8.Wash hands after practical work.

9.Do not play or run inside the laboratory.

10.Never return unused chemicals to their original containers unless instructed.

STEP 4: MEANING OF HAZARD

A hazard is something that has the potential to cause harm.

A chemical hazard may involve fire, explosion, poisoning, corrosion or other forms of injury.

Hazard symbols provide information about the possible dangers associated with substances.

Common hazard categories include:

Flammable Hazards: Can catch fire easily.

Corrosive Hazards: Can damage living tissue or materials.

Toxic Hazards: Can cause poisoning or serious harm.

Explosive Hazards: Can explode under certain conditions.

Oxidizing Hazards: Can cause or support combustion.

Irritant Hazards: Can cause irritation to the skin, eyes or respiratory system.

Students must learn to recognize safety symbols before working with laboratory chemicals.

STEP 5: MEASUREMENT IN CHEMISTRY

Chemistry involves measurement.

Important quantities include:Mass, Volume, Temperature, Time, Length, Amount of substance

The SI system, meaning the International System of Units, provides standard units for scientific measurements.

Some important units are:

Mass — kilogram (kg)

Length — metre (m)

Time — second (s)

Temperature — kelvin (K)

Amount of substance — mole (mol)

Volume is commonly expressed in litres (L) or cubic centimetres (cm³).

A useful relationship is:

1 cm³ = 1 mL

Therefore:

1000 cm³ = 1000 mL = 1 L

SUMMARY

The chemistry laboratory is a place for scientific investigation. Correct use of laboratory apparatus, careful measurement and strict observance of safety rules are essential for successful practical chemistry.

EVALUATION

What is a chemistry laboratory?
Explain the uses of a beaker, measuring cylinder, burette and pipette.
Why should a student never taste laboratory chemicals?
What is a chemical hazard?
Explain five laboratory safety rules.
Distinguish between mass and volume.

HOME PACKAGE

Draw and label ten common laboratory apparatus. State one use of each apparatus.

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LABORATORY FAMILIARISATION

Introduction to Chemistry