Here's why:
* Dissolving is an endothermic process: When NaNO₃ dissolves in water, it absorbs heat from the surroundings. This means that the process of dissolving is favored by higher temperatures.
* Le Chatelier's Principle: This principle states that if a change of condition is applied to a system in equilibrium, the system will shift in a direction that relieves the stress. In this case, increasing the temperature is a stress that favors the endothermic dissolving process, leading to more NaNO₃ dissolving.
In summary: As you heat up a solution containing sodium nitrate, more of the salt can dissolve in the water. This is why sodium nitrate is considered a highly soluble salt and its solubility increases significantly with temperature.
