Chemistry

Chemistry is the science of matter, especially its properties, structure, composition, behavior, reactions, interactions and the changes it undergoes.

Chemistry is sometimes called "the central science" because it connects physics with other natural sciences such as astronomy, geology and biology.

Physics also studies matter, but physics is the science of quantities of space and matter, and laws governing them. Chemistry is a branch of physical science but not a branch of physics. However, chemistry utilizes physics. For example, chemistry uses quantities like energy and entropy in relation to the spontaneity of chemical processes. It also explains the structure and properties of matter as a consequence of the physical properties of chemical substances and their interactions. For example, steel is harder than iron because its atoms are bound together in a more rigid crystalline lattice; wood burns or undergoes rapid oxidation because it can react spontaneously with oxygen in a chemical reaction above a certain temperature; sugar and salt dissolve in water because their molecular/ionic properties are such that dissolution is preferred under the ambient conditions. Synthesis is the major aspect that separates chemistry from physics and biology as sciences. Chemistry includes the knowledge (science) to design and make more complex substances from simpler ones. These new substances might then be analyzed for their physical or biological properties.

The etymology of the word chemistry has been much disputed. The genesis of chemistry can be traced to certain practices, known as alchemy, which had been practiced for several millennia in various parts of the world, particularly the Middle East.