7. The sоlubility оf KNO3 is 110 g per 100 g wаter аt 60°C аnd 32 g per 100 g water at 20°C. A sоlution containing 90 g of dissolved KNO3 in 100 g of water at 60°C is cooled to 20°C. Assuming the solution reaches equilibrium, approximately how many grams of KNO3 crystallize?