LABORATORY TECHNIQUES AND SAFETY
QUESTIONS
1. Multiple choice.
Choose the most correct answer.
(i) One of the following is not laboratory rule but it is a laboratory safety measure.
A: having adequate first aid kits in the laboratory
B: avoiding noise in the laboratory.
C: entering the laboratory after asking permission.
D: avoid eating in the laboratory
(ii) Which of the following used to protect hands egainst chemicals and body fliuids?
A: water
B: laboratory coat
C: Safety goggles
D: gloves
(iii) Is not item of first aid kit
A: drugs
B: Bunsen burner
C: water
D: safety pins.
(iv) Norbert saw the flammable sign on a box. he made the following possible interpretations. Which is the most correct?
A: the box contains firewood
B: the box contains spirit
C: the box contains paper
D: the box contains charcoal
(v) Protect and make an individual safe when he/she is working in the laboratory.
A: laboratory rules
B: laboratory safety measures
C: Warning signs
D: first aid kit
(vi) Guide and create good environment for effective investigation or learning in the laboratory.
A: laboratory rules
B: laboratory safety measures
C: Warning signs
D: first aid kit
(vii) Avoid accidents by directing an individual about the uses and storage of the chemical substances.
A: laboratory rules
B: laboratory safety measures
C: Warning signs
D: first aid kit
(viii) Before practical session ___________
A: do not enter the laboratory without permission
B: do not taste or smell chemicals
C: report any accident however small it may be
D: do not use dirty, cracked or broken apparatus.
(ix) After using test tubes in the laboratory, we wash them and put __________
A: in a beaker
B: on a test tube rack
C: on retort stand
D: in a basin
(x) _________ chemicals cause death immediately when taken into the body.
A: Oxidant
B: harmful
C: irritant
D: toxic.
2. Matching item.
Match items in list A with responses in list B
List A
(i) Used to transfer liquids into the flask.
(ii) Has symbol of cross of bones at the base of skull.
(iii) Hands protectors
(iv) Used for cooling gases
(v) Has symbol of flame with O like structure at the base
(vi) Represented by the symbol of flame
(vii) Its symbol shows the burning surface
(viii) Its symbol shows the substance that break
(ix) its symbol is x like structure
(x) Crush substances into fine particles.
List B
A: corrosive chemical
B: harmful chemical
C: explosive substance
D: mortar and pestle
E: thistle funnel
F: separating funnel
G: flammable substance.
H: toxic
I: oxidizing agent.
J: lie-big condenser
K: gloves
3. You are provided with the following apparatus
A-retort stand
B-glass measuring cylinder
C: plastic beaker
D: watch glass
E: test tube holder
F: plastic test tube
G: glass rod
H: glass measuring flask
J: tripod stand
K: stop watch
L: thermometer
M: mortar and pestle
N: tiles
O: crucible
P: wire gauze
Q: wash bottle
R: tongs
Use their respective letters to classify apparatus according to
(i) materials they made
(ii) uses
4. Define the following terms
(a) first aid
(b) first aid kit
(c) laboratory
(d) apparatus.
(e) chemistry laboratory
5. State the characteristics of good chemistry laboratory.
6. Explain how measurement of volume differs when using cylinder and burette?
7. It is recommended that a laboratory apparatus should be properly washed or wiped after use. Explain the significance for this when:-
(a) measuring volume of liquids
(b) measuring mass of the substance.
8. State the uses of the following laboratory apparatus.
(a)Spatula
(b) burette
(c) glass rod
(d) conical flask
(e) beaker
9. List four possible causes of laboratory accident.
10. State any eight chemistry laboratory rules
11. Name components of first aid kit and state their uses.
12. Name two per each of the following apparatus
(a) that measure accurate volume of liquids
(b) that measure inaccurate volume of liquids
(c) that measure volume of gases
(d) that hold other apparatus
(e) that hold chemical substances during experiment.
(f) that transfer chemical substances
13. Mention four importance of first aid.
14. State safety measures that a laboratory user should take against possible harm:
15. Why are warning signs are so important?
16: Mention laboratory practices that any chemistry must be awere with them.
17. Explain six chemical warning signs.
ANSWERS:
1. (i) A (ii) D (iii) B (iv) B (v) B
(vi) A (vii) C (viii) B (ix) B (x) D
2. (i) E (ii) D (iii) B (iv) J (v) I
(vi) G (vii) A (viii) C (ix) B (x) D
3. (i) According to the materials they made we get the following groups of apparatus
-apparatus made of glass are B, D, G, H and L
-apparatus made of plastic are:- C, F and Q
-apparatus made of metal are:- A, J, P and R
-apparatus made of Clay and asbestos are:- M, N and O
-apparatus made of glass wood is E
(ii)According to their uses we get the following groups of apparatus
-apparatus used for holding are:- A, E, J and R
- apparatus used for taking measure are:- K, L and H
-apparatus used for heating is O
-apparatus used for the chemical reaction are:- C and G
4. (a) first aid
Is a service given to the victim before being taken to the hospital for medical care.
(b) first aid kit
Is a small box in which different drugs,chemicals and instruments which are important for first aid service are kept.
(c) laboratory
Is a special room or building designed for experiment.
(d) apparatus
Are special tools and equipment which used in the laboratory.
(e) chemistry laboratory
Is a room or building which designed specifically for chemistry experiments.
5. A good laboratory has the following Features
i. Water supply system
ii. Drainage system
iii. Electricity supply
iv. Well illuminated
v. Well ventilated
vi. Door open out ward
vii. Gas supply
6. Volumes of liquid differs because measuring cylinder takes inaccurate volume while burette takes accurate volume.
7. (a) When measuring volume of liquid,
Washing helps to avoid contamination of the measured liquid with other substances whereby wiping helps to remove water content on the apparatus that may affect the volume of the liquid.
(b) when taking mass of the substance
Washing avoid contamination of the measured substamce with other substances whereby wiping helps to remove water content on the apparatus that may affect the mass of the substance.
8. a) Spatula
Used for picking chemical substances which are in powdered, crystalline or amorphous form.
(b) burette
It used to measure volume of liquids.
(c) glass rod.
Used for stirring so as to mix well the mixture components.
(d) conical flask
Used to hold and mix chemicals during experiment.
(e) beaker
Used for holding, mixing and heating liquid chemicals.
9. Possible causes of laboratory accident include.
•spillage of water or liquid solution on the floor.
•use of broken apparatus.
•improper handling of the bottles containing reagents.
•use of flammable liquids on open fire.
•use of unlabelled chemical substances.
•failure in fallowing procedure or instructions
10. The following are laboratory rules
-don't enter the laboratory without permission
-never take away reagent bottle from common shelf to your seat.
-keep apparatus and table neat and clean
-obey orders immediately
-never throw any thing in the laboratory
-avoid unnecessary walking, talking or moving in the laboratory
-never taste anything without permission
-wash your hands with soap after experiment
-report any accident immediately however small it may be.
-never eat or drink in the laboratory
-don't use laboratory apparatus for drinking or storing food.
-avoid mixing chemicals unnecessary.
-never go beyond instructions given.
-put off flames which are not in use.
-turn off water and gas taps immediately after use
11. The following items are contained in a first aid kit
•First Aid Manual
Contains guidelines on how to use the items in the first aid kit
•antiseptic
Used for cleaning wound and kill germs
•Soap
Used for washing hands, wounds and equipment
•cotton wool
Used to Clean and drying wounds
•Disposable sterile gloves
used for preventing direct
contact with victim’s body fluids
•Liniment
Used for reducing muscular pain
•Painkillers
Used for relieving pain
•Adhesive bandage (plaster)
Used for covering minor wounds
•Bandage
Used for keeping dressings in place and immobilising injured limbs
•Thermometer
Used to measure body temperature
•Sterile gauze
Used for covering wounds to protect them from dirty and germs
•Safety pins, clips and tape.
Used for securing bandages or dressing.
•Scissors and razor blades
Used for cutting dressing materials.
•Petroleum jelly
Applied on burns and used for Smoothening and
soothing skin.
•Torch
Used as source of light
•Whistle Blow
Used to call for help
•Gentian violet
Used to treat fungal infection
of the skin and
mouth. Also used for
the treatment of
serious heat burns
12. (a) apparatus that measure accurate volume of liquids include
-pipette
-burette
-volumetric flask
(b)apparatus that measure inaccurate volume of liquids include
-beaker
-measuring cylinder
(c)apparatus that measure volume of gases include
-gas jar
-measuring syringe
(d) apparatus that hold other apparatus include
-test tube holder
-retort stand
(e) apparatus that hold chemicals during experiments include
-beaker
-flasks
-test tubes
(f) apparatus that used to transfer chemical substances include
-funnels
-delivery tubes
-spatula
13. Importance of first aid.
-it helps to reduce pain
-it brings hope to the victim.
-it avoids infections.
-it reduces recovery time.
-it reduces chance for death.
14. The following are chemistry laboratory safety measures against possible harm:-
-never carry reagent bottles by their neck.
-never pick chemical by your bare hand
- don't point the open end of the test tube toward yourself or your neighbour during heating
-never use broken apparatus
-never use unlabelled chemicals or interchange labels of reagent bottles.
-never look directly into flask or test tube when reactions are taking place.
- wear protectors such as gloves, goggles and laboratory coat when conducting experiment.
-if your hair is long, it should be tied back.
-the soles of your shoes should not be slippery
15. Warning signs are so important because they show proper handling of substances and hazards when Miss-handling occur.
16. Laboratory practices that a chemist should be awere with include:-
(i) experimental procedure
(ii) apparatus sett up
(iii) carrying out experiment
(iv) observation and recording reading and changes.
(v) drawing
17. Chemical warning signs are symbols that drawn on a chemical substance to show how to handle the substance and its hazards when mishandling occur.
They include
(i) Flammable
This is a sign for the substances that catch fire easily. It indicated by the symbol if flame.
(ii) toxic
Is a symbol for substances that cause death immediately after being taken into the body.
It indicated by the symbol cross of bones at the base of skull.
(iii) harmful
Is a symbol for substances that cause diseases after being taken into the body.
It is indicated by X like structure.
(iv) oxidant
Is a symbol for substances that accelerate the burning process.
It is indicated by the symbol of flame with O like structure at the base.
(v) corrosive
Is a symbol for substances that burn the body surface.
It is indicated by the symbol of burning surface when the corrosive poured on its surface.
(vi) explosive
Is a symbol for substances that have forceful rapid reaction which involves throwing off
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