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
Si River to the large amount of silt carried by the river, it left behind a high layer of mud in the lower reaches of the Si River’s former course. The philosopher Confucius is buried on the north bank of the Si River where it passes through Qufu City. The river was also traditionally regarded as a place where the Nine Cauldrons were lost. Si River The Si River is a river in Shandong Province, China. It also ran through the area of modern Jiangsu Province until floods in 1194. The Si rises in the southern foothills of the Mengshan Mountains (蒙山),