Superficial destruction of a surface by friction, pressure, ulceration, or trauma. The wearing away of a tooth by chemical or abrasive action. Also called odontolysis. erosion. The gradual wearing away of land surface materials, especially rocks, sediments, and soils, by the action of water, wind, or a glacier.
In chemistry, the molar mass M is a physical property defined as the mass of a given substance (chemical element or chemical compound) divided by its amount of substance. The base SI unit for molar mass is kg / mol.
Atomic mass is the mass of an atom and is given in a.m.u. (atomic mass unit). However, a molar mass is the mass of one mole atoms or molecules and is given in grams. one mole is equal to Avogadro's number (#N_A=6.022xx10^23#) atoms or molecules. For example: Sodium atom has a mass of 23 a.m.u. however, the molar mass of sodium is 23g/mol.