Question

You dissolve a salt in water. How would you determine if the reaction is exothermic or endothermic??

Answer 1

How else but by measurement.....?

Explanation:

You assess the chemical reaction....

`NaCl(s) +Deltastackrel(H_2O)rarrNa^+ + Cl^-`

This reaction is SLIGHTLY endothermic, as we have to break the strong electrostatic forces between positive and negative ions. The ions in solution are the solvated or aquated species, i.e. `[Na(OH_2)_6]^+`, this is what we mean when we write `NaCl(aq)`.