Now we want to find what the final freezing and boiling point of our solution is after we mix our solute into the mixture. So we expect our boiling point to rise and our freezing point to depress or decrease. Because when you add Solutes to pure substances, that decreases vapor pressure. And if you want to learn more about vapor pressure and how it affects boiling points or freezing points, check out the video below. Now let's get back to our problem. So, before we can apply our two formulas for freezing and boiling points, or the change in temperature for freezing boiling points, we have to find the morality.