The relative atomic masses of elements are proportional measures. For example, the Ar for helium is 4.0, and the A r for carbon is 12.0. This means that carbon atoms have three times the mass of ...

Finding the percentage of an element in a compound by mass To find what percentage of a compound is a particular element, you must first calculate the relative formula mass (M r) of the compound.

Law Of Conservation Of Mass: Get here detailed information about both the laws of chemical combination. Also find out about Dalton’s atomic theory.