Branches and Concepts of Chemistry

Organic Chemistry: Focuses on carbon and hydrogen compounds; vital for industries like petrochemical, pharmaceutical, and textile.
Inorganic Chemistry: Investigates properties and reactions of elements and their compounds; encompasses a broad range of substances beyond carbon-based compounds.
Analytical Chemistry: Determines composition and structure of substances; involves separation, identification, and quantification of sample components.
Physical Chemistry: Provides theoretical and experimental framework for chemistry, including thermodynamics, chemical kinetics, and atomic/molecular structure.
Biochemistry: Studies biological molecules (carbohydrates, proteins, lipids, vitamins, enzymes, hormones, nucleic acids) and their structures, properties, and reactions.

Chemistry: The study of properties, composition, structure, and transformations of matter, including associated energy changes.
Matter: Anything occupying space and having mass, existing in solid, liquid, or gas states.
Element: A pure substance that cannot be chemically broken down into simpler substances, e.g., iron, calcium, carbon, nitrogen.
Compound: A substance formed from two or more elements with a definite percentage composition, e.g., carbon dioxide, sodium chloride.

Physical Change: Involves a change in the state of matter without altering its composition, e.g., melting ice or freezing water.
Chemical Change: Involves a change in composition resulting in the formation of new substances.

Physical Property: Observable characteristic of a substance without changing its identity; includes color, odor, luster, malleability, hardness, and electrical conductivity.
Chemical Property: A characteristic that becomes evident during a chemical change, e.g., flammability or resistance to oxidation and acids.

Law of Definite Composition: All samples of the same compound maintain the same elemental proportions, regardless of their origin.
Law of Conservation of Matter (Mass): During chemical reactions, matter cannot be created or destroyed; there is no net gain or loss of mass.