甚麼昰質量

質量mass...

計算方法最常用是用molar mass of an element or a compound * no of moles of that element or compound計出mass

Mass is the property of a physical object that quantifies the amount of matter and energy it is equivalent to. Mass is a central concept of classical mechanics and related subjects, and there are several forms of mass within the framework of relativistic kinematics (see mass in special relativity and mass in General Relativity). In the theory of relativity, the quantity invariant mass, which in concept is close to the classical idea of mass, does not vary between single observers in different reference frames