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2. LABORATORY TECHNIQUE AND SAFETY

LABORATORY TECHNIQUE AND SAFETY

What is a laboratory?

This is a special building where scientific experiments are being conducted.

What is a chemistry laboratory?

This is a special building where chemistry experiments are being conducted.

A chemistry laboratory is supplied with gas, electricity and water.

NB: Working in a laboratory is fun because a lot of interesting experiments are done but it can be a very dangerous place for you and others if safety regulations are not followed.
 

LABORATORY RULES

These are the rules that help to avoid accidents that may occur in the chemistry laboratory.

They are as follows:

  1. Ask for permission to your teacher or laboratory assistance before you enter in the laboratory.

  2. Do not run or play in the laboratory.

  3. Do not eat, drink, taste or smoke in the laboratory.

  4. Obey orders immediately from your teacher or laboratory assistance as to avoid accidents.

  5. Do not conduct any experiments unless your teacher or laboratory assistance tells you to do so.

  6. Do not switch on/off the gas and water taps till you are instructed to do so.

  7. Report accidents immediately to the laboratory teacher responsible or laboratory assistance.

  8. Wash apparatus before and after using them.

  9. Wash your hands after conducting any experiments.

  10. Observe the safety labels on the containers of the chemical and take necessary precautions.

              SAFETY MEASURE FOR A CHEMISTRY LABORATORY
 
     I/ All chemicals should be well- labelled to prevent a students

     II/ Laboratory should  contain first aid kit which will be used when people get accidents

    III/ Chemical that easily react with each other  should never be stored together

    Iv/ There should be fume chamber in the laboratory to  minimize unexpected gas leaks or emissions.

     V/ All students must wear safety glasses (goggle) at all times.

    VI/ Shoes (no sandals) must be worn at all time ,Bare feet  or open shoes are not  permitted in the laboratory.

    VII/ All students  must wear lab coat at all time .

    VIII/ All students should know the location of the extinguishers and fire blankets.

   IX/ All students should know the emergency evacuation route.

FIRST AID

Introduction

We must take precautions to avoid accidents in the laboratory. When an accident occurs it must be attended properly first.

What is first aid?

It is an immediate help/treatment given to a victim who has got an accident or injury before taking him/her to the hospital.

      1; What are the common accidents in the lab?

- Possible causes of accident in  chemistry laboratory are;

        
   2;  What is the importance of first aid?

  1. It saves the life of a victim.

  2. It reduces pain.

  3. It brings hope and encouragement to the victim.

  4. It prevents further bleeding.

  5. It helps in quick recovery of the victim's wound.

FIRST AID KIT

This is a small box consisting of different instruments and chemicals needed for first aid.

It has a sign of a red cross. It is placed in a safe and accessible place.

 

                                       INSTRUMENTS AND CHEMICALS FOUND IN THE FIRST AID KIT

              Instruments/ chemicals

                                 Uses

Pair of scissors

For holding gauze

Role of plaster

For covering wounds

Assorted bandage

For cleaning/covering wounds

Cotton wool

Used for treatment on wounds and cut

Razor blade

For cutting bandage, plaster

Gauze

For covering wounds

Safety pins

For pinning bandages

Adhesive plaster

For attaching the bandage to the skin

Forceps

For holding things such as gauze

Jar of petroleum jelly

To apply on burns

Iodine tincture

To clean fresh wounds

Gentian violet

To apply on minor wounds

Soap

To wash hands and wounds

Anti biotic solution

For cleaning wounds

Methylated spirit

For cleaning wounds

Pain killers

Reducing pain

Water

 For washing the wound

  
                                       BASIC CHEMISTRY LABORATORY

 

Laboratory is a special building where scientific experiments are conducted.

In order to do experiments we need;
                              1. Apparatus
                              
                               2. Chemicals 

1. APPARATUS

    These are instruments used to carry out scientific experiments in the laboratory.
 

CLASSIFICATION OF APPARATUS

We can group or classify apparatus into two groups;

  1. Material made (what are they made of)

  2. Uses (what are they used for)

a. MATERIAL MADE

  1. Apparatus made of glass

    Large numbers of chemical apparatus are made of glass.

    Why?
       It's because of easy observation for chemical reaction. Example: test tubes, beakers, flasks. 

  2. Apparatus made of iron.

    Example:Tongs, Bunsen burner, tripod stand

  3. Apparatus made of wood

    Example: test tube racks, test tube holders

  4. Apparatus made by clay

    Example: Tiles, evaporating dish, motor and pestle
     
  5. Apparatus made of plastic

    Example beaker washing bottle, funnels, Tiles, evaporating dish motor and pestle and tiles.


                  CHEMISTRY LABORATORY APPARATUS  ACCORDING TO THEIR USES

  1. Apparatus used for holding liquid i.e. beakers ,test tubes ,flat bottomed flasks and conical flasks.

  2. Used for measuring liquid i.e. measuring cylinders ,burette ,beakers and pipette.

  3. Used for measuring solids i.e. spring balance, pan balance, beam balance, chemistry balance.

  4. Used for heating i. e. crucibles, evaporating dishes, test tubes.

  5. Used for holding and supporting i.e. test tube racks ,tongs ,tripod stand and clamp.

  6. Used for boiling i.e. cork borers.

  7. Used for transferring liquid i.e. dropper funnels.

  8. Used for transferring solids i.e. spatulas.

                                                               CHEMICAL APPARATUS AND THEIR USES

                               Apparatus

                                 Uses

Test tube

For heating

For watching or observation of reactions

For holding liquids

Beaker

For holding liquids

For heating

For observations

Filter funnel

For transferring liquids

Thistle funnel

Used for transferring liquids

Dropping funnels

Used for transferring liquids

Separating funnels

Used for separating immiscible liquid example kerosene and water

Round bottomed flask

Used for mixing reagents in preparation experiment

Conical flask

Used for mixing reagents during experiments

Flat bottomed flask

Used for heating reagent during experiment

Distilling flask

Used in distillation process

Measuring cylinder

Used for measuring volumes of liquids

Dropper

Used for transferring solution from a container

Watch glass

Used for holding a solid sample

Pipette

Used for delivering or measuring fixed volumes of liquids.

Burette

To provide control of the volumes of liquid during experiments and also to measure an accurate volume.

Volumetric flask/Graduated

 

For measuring accurate volumes of liquids

-For preparing solution of accurate concentration e.g. titration

Spatula

Handling chemicals and transferring them to the container.

Tripod stand


 

For supporting containers during heating

Wire gauze

Prevent flame from direct heating

Support apparatus on tripod stand

Motor and pestle

For grinding solid chemicals to powder

Trough

For holding water and below the shelf during preparation of gases

Test tube brush

For cleaning of test tubes

Tongs

For holding hot objects when heating.

Delivery tube

For preparation of gases

Retort stand

For supporting other pieces of apparatus

Condenser

For cooling water vapor to form water during distillation

Gas jar

For collecting gases

Bunsen burner

Source of heat

Production of flames for heating.

U –tube

For drying gases.

Clamp

For supporting the apparatus

Beehive shelf.

For preparation of gas

Dissector
 

 

 To protect chemicals which are hygroscopic or which react with water from humidity

Test tube rack stand

 To hold/support test tubes containing chemicals

Test tube holder

 To hold/support test tube containing chemicals


 

 

 

WARNING SIGNS

Warning signs  are labels on chemical containers that help you to know what you can do or what you cannot do with different chemicals.

Warning signs help you to avoid dangerous accidents in the chemistry laboratory.

Examples of warning signs:

A harmful chemical are dangerous to your health thus it can make you sick, if it is not used properly. 



           TOXIC

A toxic chemical can cause death immediately or after a few days when they enter your body. Therefore, do not allow such chemicals to enter your body parts. E.g. The eyes, skin, mouth, or ears.

 

 
             FLAMMABLE

A flammable chemical or substance can catch fire easily. They should never be brought on an open flame. Examples ethanol, petrol,methylated spirit.

NB: Put all burners off before working with flammable chemicals.

 

 


             OXIDANT(OXIDIZING AGENT)

This is a chemical substance which supports burning substance thus materials will burn faster.

Examples: Potassium permanganate (KMnO4).





             EXPLOSIVE

This is a forceful rapid reaction which involves throwing particles at high speed.  It’s very dangerous to keep explosives in a glass container.

Why?
   Because if an explosion occurs, glass will fly around the place and cause injuries to people, so handle with care all chemicals containing explosive signs.




              CORROSIVE

A corrosive chemical is a substance that can burn your skin. It causes blindness if it gets into your eyes. Pour a lot of water on the affected part so as to reduce concentration of the chemical or substance.

Examples of corrosive chemicals are;

 

 

 

                                                             REVIEW  QUESTIONS


1. (I) Define the word laboratory .

   (II) Mention at least  ten chemistry laboratory rules .

2. Mention and explain the safety measures needed to avoid accidents in chemistry laboratory.

3. (i) Identify possible causes of accidents in a chemistry laboratory

   (ii) Mention all the items found in a first Aid kit.

4.Give the names of three apparatus used in a chemistry laboratory  in each of the following below;

    a/ (i)Apparatus for holding thing_________,____________,_____________.

        (ii)Apparatus for taking measurements_________,____________,_________.

        (iii)Apparatus for heating  purpose _________,_____________,___________.

        (iv)Apparatus for doing chemical reactions _________,_________,_________.

   b/Give the user of each chemistry apparatus you have mentioned apparatus.

5. (a) Define the word warning signs

    (b) Draw and label the basic chemical warning signs.

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