[Ballistic]

I have a few old chemicals such as Iron III Chloride which have absorbed more water than they can hold.


Is there a cheap method to burn off the water without using more chemicals up? e.g. leaving somewhere warm?

Can you work out from the chemical properties, what temperatures and lengths of time are required to do so?

Any help appreciated with my practical chemistry as per usual!

[Arkcon]

Gentle heat is what you need, but it will depend on the chemical how much and for how long.  Generally, when we want to dry anything in a lab, we use the 100 C oven, and it has its open container of desiccant in there,to soak up moisture as its released.  The desiccant gets dried by the oven afterward.

[Ballistic]

OK Brilliant. Can one determine what temperature will drive off water from the chemical's boiling or melting points, or is it more to do with properties of the water, e.g. the boiling point of water ?

[Arkcon]

Not really.  Se, we only really worry about decomposing the chemical itself.  Outside of that, and dry heat with a vent to allow water vapor to escape will work.