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Chemistry · Chapter 1: Introduction to Chemistry
Branches of Chemistry
The main branches of chemistry: physical, organic, inorganic, analytical, biochemistry, industrial, nuclear and environmental chemistry, with examples.
Key termRememberExampleWatch out
01Concept
Chemistry covers millions of substances, so it is divided into branches. Each branch studies one kind of substance or one kind of question.
| Branch | What it studies | Example |
|---|---|---|
| Physical chemistry | The laws and theories behind chemical changes: energy, speed of reactions, equilibrium | Why a reaction goes faster when heated |
| Organic chemistry | Compounds of carbon and hydrogen (hydrocarbons) and their derivatives | Petrol, plastics, sugar, medicines |
| Inorganic chemistry | Elements and compounds other than organic compounds | Salt, metals, acids, cement |
| Analytical chemistry | Finding what a substance contains (qualitative) and how much (quantitative) | Testing purity of milk; checking iron in water |
| Biochemistry | Chemical reactions inside living things | Digestion, respiration, DNA |
| Industrial chemistry | Making chemicals on a large scale in factories | Fertiliser, cement, sugar and soap industries |
| Nuclear chemistry | Changes in the nucleus of atoms, radioactivity | Nuclear power; radioactive isotopes in hospitals |
| Environmental chemistry | Chemicals in air, water and soil and how they affect life | Smog in Lahore; polluted water |
02Real World Examples
Quality control in factories
Analytical chemists in sugar, cement and fertiliser factories test samples every day to check quality.
Blood tests
A blood sugar or cholesterol test is biochemistry in action.
Textile dyes
Pakistan's textile industry uses dyes made by organic chemistry.
Cancer treatment
Radioactive isotopes used to diagnose and treat cancer come from nuclear chemistry.
03Practice Questions
Try to answer in your own words first, then open the model answer.
Short questions
Q1.Define organic and inorganic chemistry with one example each.Show answer
Answer
- Organic chemistry: the study of carbon and hydrogen compounds and their derivatives. Petrol, sugar.
- Inorganic chemistry: the study of elements and compounds other than organic compounds. Common salt, sulphuric acid.
Q2.What is analytical chemistry? Name its two types.Show answer
Answer
Analytical chemistry finds out what a substance is made of and how much of each part is present.
- Qualitative analysis: what is present.
- Quantitative analysis: how much is present.
Q3.Differentiate between biochemistry and environmental chemistry.Show answer
Answer
- Biochemistry studies the chemical reactions inside living things, such as digestion.
- Environmental chemistry studies chemicals in air, water and soil and their effects, such as smog.
Q4.Which branch of chemistry studies the speed of reactions and energy changes?Show answer
Answer
Physical chemistry. It deals with the laws and theories behind chemical changes, such as reaction rates, energy and equilibrium.
Long questions
Q5.Describe the main branches of chemistry with examples.Show answer
Answer
- Physical chemistry: laws behind chemical changes. Rates of reaction.
- Organic chemistry: carbon compounds. Plastics, petrol.
- Inorganic chemistry: all other elements and compounds. Metals, salts.
- Analytical chemistry: what and how much is present. Water testing.
- Biochemistry: chemistry of living things. Digestion.
- Industrial chemistry: chemicals made on a large scale. Fertilisers, cement.
- Nuclear chemistry: changes in the nucleus. Radioisotopes in medicine.
- Environmental chemistry: chemicals in the environment. Air and water pollution.