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
The Net (substance) The Net (substance) The Net, in alchemy, is an alloy of copper and iron, whose crystal structure induces a network pattern on its surface. It was described in the 17th century by Sir Isaac Newton. Newton produced the substance by following what he regarded as a recipe, encoded in classical mythology, for part of the process of achieving the philosopher's stone. The relevant myth involved the god Vulcan finding his wife Venus (alchemical symbol for copper) in bed with the god Mars (alchemical symbol for iron) Newton's interpretation rested on typical alchemical associations, construing Vulcan as a stand-in for fire,