Acertain salt is known to have a solubility in water of 31.6g/100g water at 100°c and 13.2g/100g water at 20°c. the salt is dissolved in 240 g of water at 100°c until no more solid will dissolve. how much salt will crystallize out when the solution is cooled to 20°c? ?

44.16 g of salt will crystallize

Explanation:

The salt will be added untill the solution became saturated, it means it will have  the total amount of salt the solvent can dissolve. The amount of salt will be the solubility multiplied by the mass of the solvent.

So, for 100ºC, the maximum salt that can be dissolved in 240g of water is:

31.6g/100g * 240 g = 75.84 g of salt

75.84 of salt is added to the water at 100ºC.

The maximum salt that can be dissolved in water at 20ºC is:

13.2g/100g * 240g = 31.68 g

So, the rest will crystallize:

75.84 - 31.68 = 44.16 g of salt will crystallize

it is reliable if two scientists recorded it