A chemical by definition is any substance consisting of matter; this includes solids, liquids, and gas. Chemicals can either be of a pure substance or a mixture of substances. A chemical substance such as water (H2O) is a pure chemical because it has the same molecules and combination throughout its structure.
Harnessing the power of chemistry for computing might lead to a new unifying paradigm coping with the rapidly increasing complexity and autonomy of computational systems. Chemical computing refers to computing with real molecules as well as to programming electronic devices using principles taken from chemistry.
Computational chemistry is also used to study the fundamental properties of atoms, molecules, and chemical reactions, using quantum mechanics and thermodynamics. Computational chemists use mathematical algorithms, statistics, and large databases to integrate chemical theory and modeling with experimental observations.