💛 Unsaturated vs Saturated vs Super Saturated Flashcards
(6 cards)
Someone hands you an aqueous solution of sodium acetate. Describe what you would do to see if
that solution is saturated or not?
Add a small amount of sodium acetate, stir it up, and see if it dissolves or not. If it doesn’t dissolve, it is saturated. If it does, it is unsaturated.
Someone gives you a beaker containing an aqueous solution of potassium nitrate. You want to know if the solution is saturated. What should you do?
Add a small amount of solid KNO₃ and stir.
If it dissolves → the solution is unsaturated.
If it doesn’t dissolve → the solution is saturated.
You have a glass of sugar water at room temperature and you’re not sure if it’s saturated. Describe how you’d test this.
Add a small amount of solid sugar and stir.
If it dissolves → unsaturated.
If it stays undissolved → saturated.
Describe in detail how you would make a super saturated solution of potassium chloride at 0°C
using the following data. The solubility of potassium chloride at 0°C is 2.71 g KCl in 100 g of water. The
solubility of potassium chloride at 25°C is 37.0 g KCl per 100 g water.
Dissolve 37.0 g of KCl in 100g of water at 25 C (room temperature). Slowly cool it down to 0 C. If no KCl falls out, it is super saturated.
The solubility of sodium acetate is 119 g per 100 g of water at 100°C and 76 g per 100 g at 20°C.
You dissolve 119 g of sodium acetate in 100 g of water at 100°C. You then cool the solution to 20°C slowly and no crystals form.
What kind of solution do you have at 20°C?
Supersaturated, because the solution contains more than 76 g/100 g (its solubility at 20°C) and no crystals have formed yet.
Describe how to make a supersaturated solution of potassium nitrate (KNO₃) using this data:
Solubility at 60°C = 109 g/100 g water
Solubility at 25°C = 38 g/100 g water
Heat 100 g of water to 60°C.
Dissolve 109 g of KNO₃ fully (saturated at 60°C).
Cool the solution slowly to 25°C without disturbing it.
If no crystals form, the solution is supersaturated at 25°C.
