Final answer:
The decomposition of the hydrate Na2SO4·10H2O results in the formation of anhydrous sodium sulfate Na2SO4 and the release of water vapor.
Step-by-step explanation:
The equation for the decomposition of the hydrate Na2SO4·10H2O is written as:
Na2SO4·10H2O(s) ⇒ Na2SO4(s) + 10H2O(g)
In this reaction, Na2SO4 or sodium sulfate is the anhydrous salt. The decomposition of a hydrate involves heating the compound to remove the water molecules that are chemically bound to it, which in this case are represented by 10H2O (gaseous water vapor).