The solubilties of most ionic solids increase as the temperature increases.
Dissolving of a solid in water is, in most cases, an endothermic
reaction. In dissolving, as in melting, a solid becomes a liquid. It
takes more energy to be a liquid than to be a solid at the same
temperature. When the solution becomes saturated at any temperature, a
dynamic equilibrium is established between the dissolved and undissolved
solid. When heat is added that results in a higher temperature, the
extra heat favors the endothermic reaction, and more solid dissolves
rather than crystallizes until new equilibrium system is established
again. Hence, at a higher temperature, more solid is dissolved in
water. This increases the solid's solubility.
Hope this helps mate =)
