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.
Molar Mass is how much one mole weighs of a particular compound. You can have a mole of hydrogen and a mole of helium but the mole of helium is going to way twice as much because a hydrogen has 1 proton+neutron whereas the helium has 2 proton+neutron pairs. The AMU is a unit of mass measurement on the atomic scale. 1 mole of 1 AMU weights out to 1 gram. By knowing the AMU of an atom or compound you automatically know its molar mass.