Chemistry is, the branch of science concerned with the properties, composition
and structure of substances and the changes they undergo when they combine or
react under specified conditions. Chemistry can be divided into branches
according to either the substances studies or the types of study conducted. The
primary division of the first type is between inorganic 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