[silverace42]

So i'm having a bit of a chemical mathematics problem that stems from a theoretical scenario i've created. This scenario essentially involves placing a fixed mass of a hydrate into a sealed container and then heating the vessel to release the waters of hydration. working through the mass and density of the hydrate this should release enough water to make the volume of the material inside the container greater than the actual container. For example; hydrating a 100mL (146g) sample of Sodium Carbonate Decahydrate leaves us with 91.9mL of water and 21.3mL of anhydrate, for a total of about 113mL. I want to calculate the pressure generated by this expansion assuming the pressure did not immediately re-hydrate the carbonate. I've tried using the compress ability and bulk modulus formulas but i can't seem to make it work. Help would be appreciated.     

[Hunter2]

Don't mix Volume with Mass.  146 g Na₂CO₃ x 10 H₂O MG = 286 g/mol creats 91,9 g H₂O and 54,1 g waterfree soda.

The only liquid or steam can be the water later one depending on the temperature and pressure.
The 54 g Na₂CO₃ has also a volume depending on its density. Density is 2,51 g/cm³. In this case its 21,55 ml.
This you can subtract from the given container of 100 ml what means you have 78,4 ml left. If temperatur is more then 100 °C

you can calculate p = nRT/V

If lower the hydration will not take place.

[curiouscat]

Won't some iteration be needed. Say p in your last step came to be 2 atm. If T was 101 C then it means the water was no longer steam so PV=nRT cannot be applied.

[silverace42]

where did you get the figure of 100 Celcius to activate the hydration? Is this a generally accepted figure? Additionally i think the gas laws will not apply to this scenario as the pressure will keep the water in a liquid form as curiouscat said.