How can you make sure that all of the water of hydration is removed?

Solution:

For that we have weigh the compound and heat it.  

If the weight before the heating and after heating is in equal then we can say the water in hydrated compound has been still there.  

But if the weight is change or less, then we must say that the water is lost.

adding or remove a gaseous reactant or product changes the concentrations. if the concentration of reactant or product is increased, the system will shift away from the side in which concentration was increased (i.e. if the concentration of reactants is increased, the system will shift toward the products. if more products are added, the system will shift to form more reactants). conversely, if the concentration of reactant or product is decreased, the system will shift toward the side in which concentration was decreased (i.e. if reactants are removed, the system will shift to form more reactants. if the concentration of products is decreased, the equilibrium will shift toward the products).

explanation: