Question

Define and describe the gravimetric process to determine the formula of a hydrate

Answer 1

Typically

hydrate = Salt * xH2O

in which x = number of hydrate present in the salt

Total mass of hydrate

mass = initial mass; assume this is salt + x*water

then...

once we have the actual value

heat sample, H2O must vaporize

Salt remains as Salt alone

final mass = salt only

then

difference in mass = (Hydrate) - (Salt alone) = humidity out

this is, the mass of H2O

now...

change to moles

mol of salt vs. mol of H2O

ratio will be "x"

i.e.

1 mol of salt per 6 mol of H2O will make x = 6 value

Salt * 6H2O (for example)