Amount of substance Amount of substance Amount of substance is a standard-defined quantity that measures the size of an ensemble of particles, such as atoms, molecules, electrons, and other particles. It is sometimes referred to as chemical amount. The International System of Units (SI) defines the amount of substance to be proportional to the number of entities present. The SI unit for amount of substance is the mole. It has the unit symbol mol. The proportionality constant is the inverse of the Avogadro constant. The mole is defined as the amount of substance that contains an equal number of elementary entities as there
Tog (unit) G in W/mK then a handy backronym for remembering what Tog means is "10/G", or "Ten Over G." Tog (unit) The tog is a measure of thermal insulance of a unit area, also known as thermal resistance. It is commonly used in the textile industry and often seen quoted on, for example, duvets and carpet underlay. The Shirley Institute in Manchester, England developed the tog as an easy-to-follow alternative to the SI unit of mK/W. The name comes from the informal word "togs" for 'clothing', which itself was probably derived from the word "toga", a Roman garment. The basic unit