Week 5 – Jss 2 Third Term Basic Science Lesson Notes

WEEK 5: CHEMICALS

DEFINITION OF A CHEMICAL:
A chemical is a distinct compound or substance especially which has been artificially prepared or purified.
A chemical is any basic substance that is used in or produced by a reaction involving changes to atoms or molecules.
CLASSES OF CHEMICALS.
Chemicals can be divided into two classes;

1. Chemicals based on use.
2. Chemicals based on hazardous nature.

    

Chemicals based on use include the following;

1. Pharmaceuticals.
2. Cosmetics.
3. Nuclear.
4. Agro chemicals.
5. Industrial chemicals.
6. Laboratory chemicals.

   Chemicals based on hazardous nature;

   1. Highly hazardous and toxic chemicals.
   2. Moderately hazardous and toxic chemicals.
   3. Non- hazardous and toxic chemicals.

EXAMPLES OF HAZARDOUS AND TOXIC CHEMICALS:

1. Ammonia
2. Bleach
3. Over cleaner( sodium hydroxide)
4. Toilet bowl cleaners (hydrochloric acid).
5. Car wash and polish
6. Lice shampoo
7. Flea powders
8. Pesticides
9. Tar and bug remover
10. Sodium or calcium hypocrite.
11. Triclosan
12. Formaldehyde
13. Phenol
14. Nitrobenzene
15. Trichloroethane
16. Perchloethylene
17. Sulphric acid
18. Cytotoxic agents

• EVALUATION: define chemicals
• Classify chemicals based on the following:
• Use

   

• Hazardous nature

ASSIGNMENT: Give why bottles should be labelled.