What is the standard enthalpy change of solution of sodium nitrate?

Answer 1

You need to clarify your question. If you're asking what the definition is, or what your statement means, then I'll shoot at that.

The standard enthalpy change is the amount of energy absorbed or released when solid sodium nitrate dissolves in water to form a solution with a concentration of 1 M.

If that's not what you're after, try again...