What is chemistry, what do chemists do?

Chemistry is a science that describes the physical properties, composition, structure and reactions of matter.

To understand this definition more clearly we need to define some terms.

Atom - The smallest building block of matter.*

Molecule - Groups of atoms held together in a specific connectivity and shape

Matter - Anything that has mass and occupies space.

Matter that contains only one type of atom is called an element, i.e. oxygen, nitrogen, carbon, gold, uranium, etc. All known elements are contained in the periodic table, and each is represented by a symbol.

Chemistry - the study of atoms\, made of nuclei (conglomeration of center particles) and electrons (outer particles), and the structures they form.

Chemistry' (from Egyptian kēme (chem), meaning "earth"[1]) is the science treating matter at the atomic to macromolecular scale, the reactions, transformations and aggregations of matter, as well as accompanying energy and entropy changes during these processes. In short, chemistry studies molecules, crystals, and metal/nonmetals and is concerned with the composition and statistical properties of such structures, as well as their transformations and interactions to become materials encountered in everyday life. According to modern chemistry, the physical properties of materials are generally determined by their structure at the molecular or atomic scale, which is itself defined by interatomic electromagnetic forces, and laws of quantum mechanics and thermodynamics from various fields of physics. Robert Boyle (1661), Antoine Lavoisier (1787), and John Dalton (1808) can be considered the three fathers of modern chemistry,[2] while some consider the earlier chemist Geber (d. 815) to be the "father of chemistry".[3][4][5]

Branches of Chemistry

Chemistry can be divided into branches according to either the substances studied or the types of study conducted. The primary division of the first type is between inorganic chemistry and organic chemistry. Divisions of the second type are physical chemistry and analytical chemistry.

The original distinction between organic and inorganic chemistry arose as chemists gradually realized that compounds of biological origin were quite different in their general properties from those of mineral origin; organic chemistry was defined as the study of substances produced by living organisms. However, when it was discovered in the 19th cent. that organic molecules can be produced artificially in the laboratory, this definition had to be abandoned. Organic chemistry is most simply defined as the study of the compounds of carbon. Inorganic chemistry is the study of chemical elements and their compounds (with the exception of carbon compounds).

Physical chemistry is concerned with the physical properties entropy that occur during chemical reactions and phase transformations (see states of matter). of materials, such as their electrical and magnetic behavior and their interaction with electromagnetic fields. Subcategories within physical chemistry are thermochemistry, electrochemistry, and chemical kinetics. Thermochemistry is the investigation of the changes in energy and Electrochemistry concerns the effects of electricity on chemical changes and interconversions of electric and chemical energy such as that in a voltaic cell. Chemical kinetics is concerned with the details of chemical reactions and of how equilibrium is reached between the products and reactants.

Analytical chemistry is a collection of techniques that allows exact laboratory determination of the composition of a given sample of material. In qualitative analysis all the atoms and molecules present are identified, with particular attention to trace elements. In quantitative analysis the exact weight of each constituent is obtained as well. Stoichiometry is the branch of chemistry concerned with the weights of the chemicals participating in chemical reactions.