C.2 Questions #1-3

1)
a. What mass (in grams) of potassium nitrate (KNO3) will dissolve in 100g water at 60°C?
b. What mass (in grams) of potassium chloride (KCl) wil dissolve in 100g water at the same temperature?

a. 105g of potassium nitrate will dissolve in 100g water at 60°C.
b. 45g of potassium chloride will dissolve in 100g water at 60°C.

2)
a. You dissolve 25g potassium nitrate in 100g water at 30°C, producing an unsaturated solution. How much more potassium nitrate (in grams) must be added to form a saturated solution at 30°C?
b. What is the minimum mass (in grams) of 30°C water needed to dissolve 25g potassium nitrate?

a. 20g of potassium nitrate must be added to form a saturated solution at 30°C.
b. 45g is the minimum mass of 30°C water needed to dissolve 25g potassium nitrate.

3)
a. A supersaturated solution of potassium nitrate is formed by adding 150g KNO3 to 100g water, heating until the solute completely dissolves, and then cooling the solution to 55°C. If the solution is agitated, how much potassium nitrate will precipitate?
b. How much 55°C water would have to be added (to the original 100g water) to just dissolve all of the KNO3?

a. If the solution is agitated, 55g potassium nitrate will precipitate.
b. 110.2°C water would have to be added to the original 100g water to just dissolve all of the KNO3.