Topic 2: LABORATORY TECHNIQUES AND SAFETY – Chemistry Notes Form One
RULES AND SAFETY PRECAUTIONS IN CHEMISTRY LABORATORY
What is a laboratory?
A laboratory is a special room or building used for doing scientific experiments
Chemistry laboratory is a special room where chemical experiments are conducted
CHARACTERISTICS (QUALITIES) OF A GOOD CHEMISTRY LABORATORY.
A good chemistry laboratory
(i) Should have water, gas and electric supply
(ii) Should have large windows for good ventilation and light
(iii) Should have more than one door (exits) opening outward
(iv) Should have fume chamber for experiments which produces toxic gases
(v) Should have a chemical store for keeping laboratory apparatus, chemicals and reagents
(vi) Should have preparation room for technician to sit and design scientific experiments
(vii) Should have drainage system
LABORATORY SAFETY MEASURES
Meaning: Laboratory safety measures are measures which put risks to a minimum level so as to
minimize or eliminate injuries and exposure to harmful substances.
IMPORTANCE OF LABORATORY SAFETY MEASURES
(i) Minimize or eliminate injuries
(ii) Minimize or eliminate exposure to harmful substances
(iii) Protect the environment from being exposed to harmful substances
The following are some of the safety measures to be considered in the laboratory
(i) The laboratory should be equipped with the working fire extinguishers fitted in accessible position.
(ii) Laboratory floors should not be polished to avoid slippery
(iii) Each laboratory should contain at least one first aid kit with all the necessary items.
(iv) Stored chemicals should be inspected regularly to ensure no use of expired chemicals.
(v) All apparatus should be checked regularly to ensure they are safe to use
(vi) All chemicals containers should be well-labelled to prevent accidental use of wrong substances
(vii) Wear appropriate protective clothing to minimize exposure to hazards to access and use.
(viii) Refrigerators and freezers used in the laboratory should be labelled “For chemical use only”
(ix) Chemicals which can easily react with each other should not be stored together
(x) Cup boards, storage cabinets and drawers should have locks
(xi) Emergency exits should be present and easy to access and use. Doors should open outward.
(xii) Gas cylinders should be labelled, stored well and supported. They should be in good working condition at all times
(xiii) Fume chamber should be labelled. It should be kept in a good working conditions to minimize gas leakage.
(xiv) There should be a manual or instructional guide on how to treat spills of different chemical substances.
(xv) All laboratory users should wear appropriate clothing (protective gears) to minimize exposure to hazards.
(xvi) Containers for chemicals should be checked regularly to ensure that they do not leak.
(xvii) Equipment for monitoring accidents such as fire should be installed to give alerts of any possible dangers.
(xviii) Any chemical spills should be cleaned immediately
(xix) Flammable chemicals should never be heated over an open flame
(xx) Keep the doors and windows open during experiments
(xxi) Never use broken apparatus
HANDLING CHEMICALS SAFELY
Chemicals in the laboratory are not always safe therefore, you should know their hazards by checking the safety signs labelled on their containers. All chemicals which are not correctly labelled should be removed from the laboratory and destroyed.
CHEMICAL WARNING SIGNS (HAZARD SYMBOLS)
Meaning; Warning sign is a safety symbols found on chemical containers to ensure safety in the laboratory and in other fields.
On chemical containers symbols are used especially for labelling chemicals that are hazardous.
The following are some of the warning signs used in the laboratory and their meaning as shown in the table
(i) Toxic (ii) Irritant (iii) Flammable
(iv) Oxidant (Oxidizing agent) (v) Corrosive (vi) Explosive
(vii) Danger of electric shock (viii) Fragile (ix) Radioactive
(x) Careful (xi) Keep away from water (xii) Health hazard
(xiii) Harmful
Other safety signs and their meaning are as follow
EXERCISE
1. Imagine you have been given a chance to advise the school building committee on how should the laboratory building look like. What could be your advice?
2. What dangers are likely to occur if a laboratory user fails to follow the laboratory safety measures?
3. How can safety signs be used to prevent accidents and injuries in the laboratory?
LABORATORY RULES
Definition: Laboratory rule is a statement that explain what to do or not to do in the laboratory
OR
Laboratory rule is the set of regulation governing practical activities in the laboratory
IMPORTANCE OF LABORATORY RULES
Laboratory rules are important in order
(i) To have successful practical activities
(ii) To avoid hazards
Laboratories rules are divided into three parts include
(i) Before practical activities
(ii) During practical activities
(iii) After practical
LABORATORY RULES BEFORE PRACTICAL ACTIVITIES
(i) Do not enter in the laboratory without the permission or presence of the teacher or laboratory technicians.
(ii) Keep the windows open for proper ventilation.
(iii) Master the location of all exits
(iv) Dress properly for the laboratory activities. Wear laboratory coats and safety goggles. Do not wear loose or floppy
Clothing. Tie back long hair. Do not wear shorts, or walk barefoot or in sandals. Roll up long sleeves.
LABORATORY RULES DURING PRACTICAL ACTIVITIES
(i) Read instructions carefully before you start any activity
(ii) Do not eat, drink, play, run or smoke in the laboratory
(iii) Do not taste or smell chemicals unless advised on how it should be done
(iv) Do not spill liquids on the floor
(v) Do not use dirty, cracked or broken apparatus
(vi) Do not touch any electrical equipment with wet hands
(vii) Turn off any gas or water taps that are not in use
(viii) Do not remove any chemical or equipment from the laboratory without permission
(ix) Keep inflammable substances away from open flames
(x) Read the labels on chemical containers to be sure you have the right substance. Do not interchange labels
(xi) Report any breakages or accidents to the teacher or laboratory assistant immediately
(xii) Replace covers and stoppers on the containers after using the chemicals
(xiii) Only perform the intended experiments. Do not set up your own experiments or interfere with someone’s experiment.
(xiv) In case of a gas leakage turn off all the gas taps and open the windows. Leave the laboratory immediately.
(xv) Use fume chamber when doing experiment which produces harmful gases and fumes
(xvi) When heating substances do not point test tubes or burners towards yourself or other people
(xvii) If you do not understand something, ask your teacher or the laboratory technician before proceeding
(xviii) Use lighter or wooden splint to light burners. Do not use papers. Always strike the match before turning on the gas tap.
(xix) Wash off any chemical spillage on your skin or clothes with plenty of clean water
LABORATORY RULES AFTER PRACTICAL ACTIVITIES
(i) Clean up the equipment and store them safely
(ii) Turn off gas and water taps.
(iii) Clean the working surfaces, benches and sinks
(iv) Wash your hands with soap and running water.
(v) Dispose of any wastes appropriately. Use the litter bins and not the sinks to dispose any solid waste.
(vi) Do not pour concentrated chemicals into the sinks.
(vii) Do not return unused chemicals to their original containers
EXERCISE
1. Why should chemicals in the laboratory be labelled and always well closed?
2. You have been assigned by your chemistry teacher to present the benefits of having laboratory rules. Use the following rules to prepare your presentation:
(a) Do not eat, drink, smoke, play or run in the laboratory
(b) Do not taste or smell a chemical or anything unless you have been instructed on how to do it.
(c) Use a fume chamber when carrying out experiments which produce harmful gases and vapours.
(d) Perform the intended experiments only.
3. Give reasons to support each of the following statements:
(a) A laboratory should be equipped with working fire extinguishers
(b) A laboratory should have large windows.
(c) Concentrated chemicals should not be poured into sinks
FIRST AID AND FIRST AID KIT
FIRST AID
Definition: First aid is the help given to a sick or injured person before getting professional medical help
OR
First Aid is the help given to injured or sick person before taking him or her to Hospital
OR
First Aid is all that we can do to help an accident victim before we can get professional medical help in hospitals
First Aider: First Aider is a person who is provides Ffirst Aid.
QUALITIES OF FIRST AIDER
A good first aider should have the following qualities
(i) should have knowledge of first aid principles
(ii) Should be physically fit so that can perform first aid tasks such as lifting
(iii) Should have good communication skills so that can communicate clearly with injured person others
(iv) Should have good discipline so that can follow first aid principles.
(v) Should be patient and tolerant
(vi) Should have confidence in decision making.
IMPORTANCE OF FIRST AID
1. It reduces pain and suffering
2. It reduces the likelihood of death (It save life)
3. It shortens recovery time
4. It prevent permanent disability
5. It prevents the victim’s condition from getting worse
6. It brings hopes and encouragement to victim
POSSIBLE CAUSES OF ACCIDENTS IN THE LABORATORY ARE:
The following are various causes of accidents in the laboratory
Some possible causes of accidents in the laboratory include:
(i) Spilled liquids left on the floor may cause slipping and falling.
(ii) Accidental swallowing of harmful chemicals
(iii) Poor ventilation may cause poisoning by inhaling harmful gases and fainting due to lack of oxygen.
(iv) Eating or drinking in the laboratory may cause food poisoning through contamination.
from harmful gases or chemicals.
(v) Improper disposal of chemical wastes may result in explosions, burns or fire
(vi) Wrong use of apparatus /equipments can results into breakage which can cause cuts
(vii) Gas leaks from the taps or cylinders may lead to fires or even explosions
(viii) Failure to follow the right experimental procedures that can lead to explosions and damage
of equipment
(ix) Use of wrong reagents due to wrong labeling or use of expired reagents may cause burning,
poisoning or damage to equipment.
(x) Chemical spills and exposure that can lead to burns and damage to body parts such as eyes and skin
(xi) Lack of adequate information on procedures and hazards related to certain practical
activities or reactants may result in burns and explosions.
(xii) Electric shock can occur if electrical appliances are not plugged properly or are touched with wet hands.
FIRST AID KIT
First Aid Kit is a small box which contains first aid items used to give help to sick or injured person
FIRST AID MANNUAL
First Aid Manual is the booklet which provides guideline on how to use the items in
the first aid kit
The main items in a first aid kit and their uses are:
| INSTRUMENT (CHEMICAL) | USES |
| First Aid manual / Guide | Provides guidelines on how to use the items found the first Aid Kit |
| Plaster or adhesive bandage | For covering small cuts or wounds to protect them from dirt and germs |
| Sterile gauze | Covering wounds to protect them from dirty and germs |
| Pair of scissors / razor blade | Used for cutting dressing materials |
| Cotton wool | Used for cleaning and drying wounds |
| Pain killer eg paracetamol | Used for reducing pain / Relieving pain |
| Clinical thermometer | Used for measuring the body temperature |
| Petroleum jelly | Used for applying on burns and soothing/ smoothing dry (chapped) skin and sore skin |
| Torch | Used as source of light |
| Safety pins | Used for securing bandage |
| Iodine Solution (Iodine Tincture) | Used for preventing infections in fresh cuts, burns and scrapes Also, it is used for cleaning fresh cuts |
| Soap | Used for washing wounds, hands and equipment |
| Antibiotic solution | Used for cleaning wound |
| Whistle | Used for calling for help |
| Disposable sterile gloves | Used for covering the hands to avoid infecting wounds and to prevent direct contacts with a victim’s body fluids |
| Liniment | Used for reducing muscle pain |
| Gentian violet (G.V) | Used for treatment of fungal infections of the skin and mouth Also, it is used for treatment of serious heat burns |
| Antiseptics eg Dettol | Used for cleaning wounds to kill germs |
| Bandage | Used for keeping dressing in place and immobilizing injured limbs |
FIRST AID PROCEDURES
The following are some of the situations / conditions that may require First Aid and the procedures to follow in giving help.
i. Burns ii. Suffocation iii. Choking iv. Bruises v. Shock vi. Electrical shock
vii. Fainting viii. Bleeding ix. Poisoning x. vomiting
1. SUFFOCATION
Suffocation is a condition in which the lungs are not getting enough oxygen causing difficulty in breathing.
This can be caused by some chemical such as sulphur dioxide and nitric acid vapour when inhaled leading to breathing difficulties.
Foam can also appear in the mouth and nostrils and victim may eventually lose consciousness.
PROCEDURE
(i) Remove the cause or remove the victim from the cause of suffocation
(ii) Ensure the victim’s airways are open for air to reach the lungs by placing the victim on his or her back.
Tilt the head backwards in order to open the airways.
(iii) Blow air into the victim’s airways using a clean material such as piece of cloth or paper and
compress the chest with both hands. Don’t use mouth to mouth resuscitation as this may
cause infections.
(iv) Keep the victim warm by using a light blanket
(v) Take the victim to nearby health care for medical help
2. BURNS
Burns are injuries resulting from the body coming into contact with heat or harmful chemicals. Scalds are burns caused by hot liquids or vapour.
EFFECT OF BURNS
Burns cause blisters on skin and if severe the skin becomes charred and peels off
PROCEDURE
(i) Lay the victim down avoiding the burnt area to touch the ground
(ii) Gently pour cold water on the burnt area for 10minutes to cool it and reduce pain.
(iii) Check breathing and pulse and be prepared to blow air into the victim’s airways if necessary.
(iii) Gently remove any jewellery, shoes or burnt clothing from the injured area. Loosen any tight clothing.
Do not remove sticking cloth to the skin
(iv) Cover the burn with a sterile gauze and wrap it loosely to avoid pressure on skin
(v) Give the victim a pain killer
(vi) Take the victim to a nearby health Centre for treatment.
CAUTION
(i) Do not break any blisters as that can cause infections.
(ii) Do not use ice as it can further damage skin.
(iii) Do not apply ointment or butter to the burn since this prevent proper heling.
(iv) In case of burns to the face and mouth or throat seek medical help immediately since they are very serious.
3. CHOKING
Choking is the blockage of the upper part of the airways by food, drink or other objects which prevent proper breathing. Signs of chocking include difficulty in speaking and breathing.
PROCEDURE
(i) Encourage the victim to cough up the object
(ii) If the object remains stuck give firm but gentle taps between the shoulder blades
(iii) Perform Heimlich manoeuvre when the object is still stuck.
The Heimlich manoeuvre involves the following:
(a) Make the person lean forward slightly and stand behind him or her.
(b) Make a fist with one hand and put your arms around the person. Grasp your fist with the other
hand near the top of the victim’s stomach.
(c) Press your fist into the victim’s abdomen and make quick upward thrusts to dislodge the object.
(d) Repeat the thrusts until the object comes
(e) Take the victim to nearby health centre for further treatment.
4. BRUISES
A bruise is a skin injury that causes a change in the colour of the skin. It is caused by a blow (hard hit) or impact that damages the blood vessels that are below the skin.
PROCEDURE
(i) Apply a cold compress such as a cloth dipped in cold water or ice wrapped in a cloth to the injury.
Keep on compressing the injury for 20 to 30 minutes to reduce swelling.
(ii) If the bruise is on the leg or foot and it covers a large area, keep the leg elevated as much as possible for
the first 24hrs
(iii) After 48hrs apply a warm clean cloth to the bruise for 10 minutes, three times a day so as to increase
blood flow to the affected area hence speeding recovery.
5. SHOCK
Shock is a condition in which the body system is unable to take enough blood to the vital organs such as heart, lungs and brain.
Shock is common with many injuries regardless of how severe they are.
Symptoms of shock
(i) Fast pulse rate (ii) Pale skin, lips and fingernails
(iii). Skin becomes cool and moist (iv) Limbs may tremble and become weak
(v) Nausea and vomiting (vi) Become restless, anxious, aggressive and finally
unconscious.
PROCEDURE
(i) Control any cause of shock that can be put right such as external bleeding.
(ii) Lay the victim down then put him/her in a shock position
(iii) Loosen tight clothing, laces and belts
(iv) Maintain victim’s body temperature by using warm covering but don’t over heat
(v) Blow air into the victim’s airway (Resuscitate) if necessary.
(vi) Take the victim to the nearby health centre for medical help immediately
ELECTIC SHOCK
It occurs when a person comes into contact with electric current and may cause injury or death. Injuries may be burns or physical injuries that results from being shocked by electric current.
PROCEDURE
(i) Break the contact between the electrical source and the victim by switching off the power source
(main switch).
(ii) If it is not possible to switch off the current, break contact between the electrical source and the victim
using a dry wooden stick or material which does not conduct electricity.
(iii) If the breathing has stopped blow air into the victim’s airways using clean material
(iv) If the victim is breathing but unconscious put him or her in the recovery position
(v) Perform First Aid for burns and shock if any.
(vi) Take the victim to nearby health Centre for medical help
CAUTION: Do not ether touch a person who is still in contact with electric current or go near the area if high
voltage electricity is suspected. Instead call for help immediately.
6. FAINTING
Fainting is a sudden loss of consciousness caused by lack of sufficient blood and oxygen to the brain. Victim feels weak, sweats and then falls down.
PROCEDURE
(i) Loosen or remove any tight clothing from the victim.
(ii) Lay down the victim on his or her back
(iii) Raise the legs of the victim (shock position) to increase the flow of blood to the brain
(iv) Keep a victim in an open place with plenty of air.
(v) Take the victim to the nearby health centre for medical help immediately if a victim dos not
recover in a few minutes.
7. BLEEDING
Bleeding is the loss of blood occurring from visible wound or internal organ. Excessive bleeding can cause death.
LIGHT BREEDING
PROCEDURES
(i) Wear protective gloves for prevention of any infections
(ii) Place a victim in a comfortable resting position
(iii) Elevate the injured part
(iv) Gently clean the wound using clean water and antiseptic or salt solution, cover the wound with sterile
Gauze.
(v) Dress the wound and bandage it.
(vi) If bleeding continues take the victim to a nearby health Centre for medical help
SEVERE BREEDING.
PROCEDURES
(i) Wear protective gloves for prevention of any infections
(ii) Using fingers apply direct pressure onto the breeding point for five to fifteen minutes.
(iii) Rise the injured part and support it in a comfortable position that does not cause pain.
(iv) Clean the wound without removing object stuck in the wound
(v) Dress the wound and bandage it.
(vi) If bleeding continues take the victim to a nearby health Centre for medical help
NOSE BLEEDING
PROCEDURE
(i) Loosen clothing around the neck and chest
(ii) Let the victim sit with his/her head tipped slightly forward.
(iii) Let the victim pinch in the nose and ask him or her to breath through the mouth for a few
minutes.
(iv) Place a wet piece of cloth at the back of the victim’s neck
(v) When bleeding stops gently clean the nostrils
(vi) Take the victim to health centre for medical help if bleeding continues.
8. POISONING
Poison is any substance that can harm the body if swallowed, inhaled or absorbed into the body through the skin. Poisons include laboratory chemicals, drugs and medicines.
SIGNS/ SYMPTOMS OF POISONING
These include (i) Nausea (ii) Vomiting (iii) Abdominal cramps or pain (iv) Difficulty in breathing (v) Diarrhoea (vi) Abnormal skin colour
PROCEDURE
(i) Call for medical assistance immediately
(ii) Meanwhile, find out what caused the poisoning
(iii) If poison is in the eye:
(a) Wash the eye with a lot of clean water
(b) Ask the victim to blink as much as possible
(c) Do not rub the eye
(iv) If poison is on the skin
(a) Remove any clothing from the affected part
(b) Wash the affected area thoroughly with a lot of water, do not apply any ointment
(v) If the poison has been swallowed:
(a) Induce vomiting if the poison is non corrosive. Non corrosive substances include medicines. You should put your finger in the victim’s throat to induce vomiting.
(b) Do not induce vomiting if the poison is corrosive. Corrosive substances include kerosene, bleaching agents, detergents, laboratory acids, bases, disinfectants, pesticides and certain toiletries.
(vi) If the poison has been inhaled, move the person to an open space where there is plenty of fresh air. Make sure you protect yourself from inhaling the poison.
(vii) Take the victim to health centre for medical help.
9. VOMITING
Vomiting is the forceful removal (discharge) of the contents of the stomach through the mouth. It can be caused by food poisoning, drinking contaminated water, inhaling poisonous fumes or overheating.
PROCEDURE
1. Give the victim lots of clear fluids, including an oral rehydration salt (drink)
2. Get medical assistance to a nearby health Centre if:
(a) There is persistent vomiting (b) The victim vomits blood (c) The victim has high fever
(d) The victim is very dehydrated. This may be observed when the mouth and the skin become very dry.
LABORATORY TECHNIQUES AND SAFETY
EXERCISE 1
1. Differentiate between First Aid and First Aid Kit
2. Name ten components of the First Aid Kit and state their uses.
3. List five possible causes of accidents in school laboratory.
4. How can you help a fellow student who has been burnt with chemicals in the laboratory?
5. Explain the importance of giving First Aid to a victim of accidents. Use any five points.
6. How can you help a person who is bleeding severely?
7. How will you give First Aid to a person who has fainted?
8. If your family member has a burn, how can you help him or her?
9. Who is responsible to receive the report of all accidents which occur in the laboratory?
10. If chemicals get into your eyes, what first thing will you do?
11. In which other areas do you find safety warning sign?
12. Why should the laboratory exit open outwards?
13. Why are the safety signs very important?
EXERCISE 2
1. Explain the importance of shock positioning a person suspected to be in shock.
2. Why is it necessary to take precautions while working in the laboratory?
3. If you were told to highlight the possible causes of accidents in the laboratory what could be your
highlights?
4. What are the different types of burns and how would you provide appropriate First Aid to each?
5. Why should a laboratory contain a First Aid Kit with all necessary items?
6. What are the key considerations treating a found to prevent infections.
7. On your field trip you found two people surrounding a person lying down suspected of Fainting. Describe how you would assess and provide the right First Aid to the victim?