Final answer:
The xH2O part of a salt formula is called a hydrate, which indicates the presence of water molecules within the compound.
Step-by-step explanation:
The name given to the xH20 part of a salt formula is a hydrate. The xH2O part of a salt formula is called a hydrate, which indicates the presence of water molecules within the compound. Hydrates are ionic compounds that have water molecules incorporated within their formula unit.
The number of water molecules associated with each formula unit of the compound is indicated by the coefficient and the formula for water, separated by a dot. For example, the hydrated form of cobalt (II) chloride is cobalt (II) chloride hexahydrate, represented by the formula CoCl2 · 6H2O.