A cycle describes the movement of any chemical element or chemical compound that cycles through the biosphere and plays a role in its stability, as well as cycling through other Earth reservoirs.

The description of the movement of any chemical element that cycles through the biosphere and plays a role in it's stability,as well as cycling through other earth reservoirs is a Biogeochemical cycle.

the formula mass of a molecule or a compound is the sum of the atomic weights of the atoms in its empirical formula

(that's what i know about formula mass)