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.
The mass of one mole of an element or compound is called its molar mass (symbol M). The molar mass of copper is 63.5 g mol -1. The molar mass of sodium hydroxide is 40 g mol -1. There is a quantity that relates to the number of particles in a mass of substance. This quantity is called the amount of substance.