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

Sep 21, 2017

$N a C l \left(s\right) + \Delta \stackrel{{H}_{2} O}{\rightarrow} N {a}^{+} + C {l}^{-}$
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. ${\left[N a {\left(O {H}_{2}\right)}_{6}\right]}^{+}$, this is what we mean when we write $N a C l \left(a q\right)$.