Now if we add all these guys up, we get something called heat of solution. And heat of solution can tell you if the solution formation is exothermic or endothermic. Now if this guy is negative, it's exothermic. And bonds formed are stronger or more stable than the bonds broken. So this bond between X and Y is greater or is stronger and more stable than that bond or this bond. If the heat of solution is positive, the bonds formed are weaker than the bonds broken.