Unit 1: Chemistry and Its Importance
Chemistry is the fundamental “central science” that explains the properties and transformations of matter. It plays a critical role in human existence by providing the knowledge necessary to meet basic needs such as food, clothing, shelter, health, and energy. By understanding how substances behave and change, society can drive advancements in agriculture, medicine, and industrial production.
1.1 Definition and Scope of Chemistry
1.1.1 Definition of Chemistry
Chemistry is the branch of science that deals with the properties, composition, and structure of substances (elements and compounds), the transformations they undergo, and the energy released or absorbed during these processes.
To understand this definition, we must look at its core components:
- Substance: A particular kind of matter with uniform properties (e.g., gold, water, table salt).
- Structure: The arrangement and relationships between the parts or elements of something complex.
- Transformation: A marked change in the form, nature, or appearance of a substance, which is always accompanied by energy changes.
1.1.2 Scope of Chemistry
Modern chemistry is divided into five main disciplines:
- Physical Chemistry: Studies macroscopic and atomic properties and phenomena in chemical systems, such as reaction rates and energy transfers.
- Organic Chemistry: The study of substances containing carbon, which is found in all living organisms.
- Inorganic Chemistry: The study of substances not primarily based on carbon, commonly found in rocks and minerals.
- Analytical Chemistry: Focuses on the composition of matter by separating, identifying, and quantifying chemicals in samples.
- Biochemistry: The study of chemical processes occurring within living things, from basic cellular functions to understanding diseases.
1.2 Relationship Between Chemistry and Other Natural Sciences
Chemistry is known as the central science because it links various fields of study together. Many branches of science overlap with chemistry:
| Overlapping Field | Description |
| Biochemistry | Overlap between Biology and Chemistry; studies chemical processes in living matter. |
| Geochemistry | Overlap between Geology and Chemistry; studies the processes controlling the composition and distribution of chemical compounds in the earth. |
| Chemical Physics | Overlap between Physics and Chemistry; investigates physicochemical phenomena using atomic and molecular physics.+1 |
| Medicinal Chemistry | Overlap between Chemistry and Medicine; involves the design, development, and synthesis of pharmaceutical drugs. |
1.3 The Role Chemistry Plays in Production and the Society
Chemistry provides essential materials across various sectors:
A. Agriculture
- Fertilizers: Chemicals used to increase crop productivity.
- Pesticides and Herbicides: Substances used to protect crops from pests and weeds.
B. Medicine
Chemistry has provided life-saving drugs and chemical agents:
- Analgesics: Painkillers used to achieve relief from pain.
- Antibiotics: Used to control infections and cure diseases (e.g., Penicillin).
- Anesthetics: Relieve pain during medical operations.
- Antiseptics: Prevent the contamination of wounds by bacteria.
- Disinfectants: Kill microbes on toilets, floors, and drains (e.g., hand sanitizers).
- Tranquillizers: Reduce tension and calm patients with mental diseases.
- Specific Treatments: Cisplatin and Taxol for cancer therapy; AZT for prolonging the life of HIV-AIDS victims.
C. Building Construction
Chemistry provides resources for safer and more durable structures:
- Materials: Glass, steel, and cement.
- Infrastructure: Used in building multi-story structures, bridges, and dams like the Grand Ethiopian Renaissance Dam (GERD).
1.4 Some Common Chemical Industries in Ethiopia
An industry is an economic activity concerned with processing raw materials and manufacturing goods in factories. Ethiopia has several medium and large-scale chemical enterprises:
| Name of Enterprise | City | Key Products |
| Chorra Gas & Chemical Products | Addis Ababa | Aluminum sulphate, sulphuric acid, plastics. |
| Ziway Caustic Soda Factory | Ziway | Sodium hydroxide (Caustic soda). |
| Abijata Soda Ash Factory | Bulbula | Soda ash (Trona). |
| Adola Magnesium Oxide Factory | Adola | Magnesium oxide. |
| Adami Tulu Pesticide Plant | Adami Tulu | Malathion, diazinon, and other pesticides. |
| Nefas Silk Paints Factory | Addis Ababa | Paints, varnishes, glues. |
| Repi Soap & Detergent P.L.C | Addis Ababa | Soap and detergent. |
| Horizon Addis Tyre | Addis Ababa | Tyres. |
Key Terminology
- Analgesics: Pain-relieving drugs.
- Anesthetics: Drugs used to relieve pain during surgery.
- Antibiotics: Drugs used to treat bacterial infections.
- Antiseptics: Substances that prevent wound contamination.
- Chemical Industry: Companies that convert natural resources into chemical products.
- Chemical Products: Substances manufactured or processed for use or sale.
- Composition: The nature of a substance’s ingredients; how a whole is made up.
- Disinfectants: Chemicals used to kill microbes on surfaces.
- Energy: Power derived from physical or chemical resources to provide light and heat.
- Matter: Anything that makes up living and non-living things.
- Property: A characteristic by which we can distinguish one substance from another.
- Structure: The arrangement of parts within a substance.
- Substance: Matter with uniform properties.
- Tranquilizers: Drugs used to reduce mental tension.
- Transformation: A change in the form or nature of a substance.
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