The Main Branches of Chemistry (and What Each One Studies)
Chemistry is a huge subject, so it is usually divided into five main branches: organic, inorganic, physical, analytical, and biochemistry. Each branch looks at matter from a different angle, and most chemists specialize in one or two of them.
1. Organic chemistry
Organic chemistry is the study of compounds that contain carbon, especially those combined with hydrogen. Because carbon atoms link together so readily, they form millions of different compounds, from the alkanes in natural gas to the proteins in your body. Organic chemistry underpins plastics, fuels, medicines, and food.
2. Inorganic chemistry
Inorganic chemistry covers everything that organic chemistry does not: the compounds of all the other elements, including metals, minerals, and salts. It explains how table salt forms, why some metals rust, and how the colored compounds of transition metals behave. Catalysts, semiconductors, and ceramics all fall within its scope.
3. Physical chemistry
Physical chemistry applies the ideas of physics to chemical systems. It asks how and why reactions happen: how fast they go, how much energy they release, and how far they proceed. Concepts such as activation energy, thermodynamics, and reaction rates all belong to physical chemistry.
4. Analytical chemistry
Analytical chemistry is about identifying what a sample contains and how much of it is present. Analytical chemists use techniques such as spectroscopy and chromatography to test the purity of drugs, detect pollutants in water, and confirm the composition of new materials.
5. Biochemistry
Biochemistry studies the chemical processes inside living things. It examines large molecules such as proteins, carbohydrates, and DNA, and explains how enzymes speed up the reactions that keep cells alive. Biochemistry sits at the boundary of chemistry and biology.
How the branches fit together
These branches overlap constantly. Developing a new medicine, for example, might use organic chemistry to build the molecule, analytical chemistry to test its purity, physical chemistry to study how it reacts, and biochemistry to understand how it works in the body.
Explore precise definitions from every branch in our A–Z Chemistry Dictionary.