Amount of substance in use in chemical engineering in the United States is the pound-mole, having the symbol lb-mol. One pound-mole is . When quoting an amount of substance, it is necessary to specify the entity involved, unless there is no risk of ambiguity. One mole of chlorine could refer either to chlorine atoms, as in 58.44 g of sodium chloride, or to chlorine molecules, as in 22.711 liters of chlorine gas at STP. The simplest way to avoid ambiguity is to replace the term "substance" by the name of the entity or to quote the empirical formula. For example: Amount of substance
Chemical Weapons Convention Chairman of the Norwegian Nobel Committee. The convention distinguishes three classes of controlled substance, chemicals that can either be used as weapons themselves or used in the manufacture of weapons. The classification is based on the quantities of the substance produced commercially for legitimate purposes. Each class is split into Part A, which are chemicals that can be used directly as weapons, and Part B, which are chemicals useful in the manufacture of chemical weapons. Separate from the precursors, the convention defines toxic chemicals as "[a]ny chemical which through its chemical action on life processes can cause death, temporary incapacitation