Chemicals – JSS2 Basic Science Lesson Note (Third Term)

CHEMICALS
A substance composed of chemical elements or a substance produced by or used in chemical processes. Chemical classes are groupings that relate chemicals by similar features. Chemicals can be classified by their structure (e.g., hydrocarbons), uses (e.g., pesticides), physical properties (e.g., volatile organic compounds [VOCs]), radiological properties (e.g., radioactive materials), or other factors. The chemical classes identified below are ones used by the Agency for Toxic Substances and Disease Registry (ATSDR) to address hazardous substances.

Classes of Chemicals

Based on use

Pharmaceutical/cosmetics e.g. Mood stabilizers: lithium and valpromide

•   Hormone replacements: Premarin

•   Oral contraceptives: Enovid, “biphasic” pill, and “triphasic” pill

•  Stimulants: methylphenidate, amphetamine

•  Tranquilizers: meprobamate, chlorpromazine, reserpine, chlordiazepoxide, diazepam, and alprazolam

•  Statins: lovastatin, pravastatin, and simvastatin.

Pharmaceutical or a drug are classified based on their origin.

Drug from natural origin: Herbal or plant or mineral origin, some drug substances are of marine origin

Drug from chemical as well as natural origin: Derived from partial herbal and partial chemical synthesis Chemical, for example, steroidal drugs

Drug derived from chemical synthesis.

Drug derived from animal origin: For example, hormones, and enzymes.

Drug derived from microbial origin: Antibiotics

•  Nuclear; Radioactive means any material having a specific activity greater than 70 Becquerel (Bq) per gram.E.g. 

1.  Fission reaction at a nuclear power plant provides enough energy to give electricity to large cities.

2.  The fusion reaction in the sun provides our planet with all the energy it needs for all the living organisms to survive.

3.   An uncontrolled fission reaction provides the destructive forces of a nuclear bomb.

•   Agrochemical or agrichemical; In most cases, agrichemical refers to the broad range of pesticides, including insecticides, herbicides, fungicides, and nematicides. It may also include synthetic fertilizers, hormones, and other chemical growth agents, and concentrated stores of raw animal manure.

•             Industries- industries that use chemicals to produce goods are called chemical-based industries; dyes, iodine solutions, methylated spirit, soaps, detergent, shampoo, cosmetics

•   Laboratory; sodium hydroxide, hydrochloric acid, tetraoxosulphate VI acid, sodium trioxocarbonate IV, potassium hydroxide, ethanol. Etc

Based on its hazardous nature;

Highly hazardous and toxic

• Explosive(picric acid, 2, 4- dinitro-phenol, organic azides), chloroform, chromic acid, phenol, acetonitrile, methanol, acetone, and acetaldehyde burn rapidly. Sodium Ignites easily

Based on moderately hazardous and toxic

•  sodium hydroxide, potassium hydroxides, organic acids, oxidizing acids, hydrochloric acid, sulfuric acid, boric acid, nitric acid, bromine

Nonhazardous and toxic.

•  nitrogen, carbon dioxide,