Relative formula mass No atoms are created or destroyed during a chemical reaction. This allows calculations to be made on the quantities of substances that react and of the products made.

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.