Avogadro constant of molecules in one gram-molecule of oxygen (exactly of oxygen, according to the definitions of the period), and this term is still widely used, especially in introductory works. The change in name to "Avogadro constant" ("N") came with the introduction of the mole as a base unit in the International System of Units (SI) in 1971, which regarded amount of substance as an independent dimension of measurement. With this recognition, the Avogadro constant was no longer a pure number, but had a unit of measurement, the reciprocal mole (mol). While it is rare to use units of 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),