Solubility �Notes

Types of Solutions

1. Saturated solution – maximum concentration of a solute dissolved in the solvent and additional amounts of it will appear as a solid. Full capacity dissolved.

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Types of Solutions

2. Unsaturated solution – A solution with less solute than the saturated solution, that completely dissolves, leaving no remaining substances.

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Types of Solutions

3. Supersaturated solution – solvent holds more solute than is normally possible at that temperature. These solutions are usually unstable and crystallization can occur by adding a seed crystal.

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• When a supersaturated solution is formed, there are several ways to get the solute to come out of the solvent and crystalize. There needs to be a place for the crystals to start to form.
• Add a seed crystal
• Shake or tap the glassware
• Click a metal coin

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https://youtu.be/ArNfbLvPzYo --> to show seed crystal

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Supersaturated Demo (Heat Solution Packs)

1. What type of solution was in the “solution pack”?

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• What happened when the metal coin was clicked?

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• List 3 things that can be done to cause a supersaturated solution to crystalize.

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• How do you make a supersaturated solution?

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Solubility Curves

• Any amount of solute below the curved line indicates solution is unsaturated at that temperature (more solute can be dissolved)
• Any amount of solute on the curved line indicates solution is saturated (full capacity of solute that can dissolve)
• Any amount of solute above the curved line in which all the solute is dissolved shows the solution is supersaturated (more than the full capacity of solute has dissolved due to heating)

1. If you added 70g of KNO₃ to100g of water at 44^OC, what type of solution would you produce?

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2. If you added 50g of KNO₃ to 100g of water at 50^OC, what type of solution would you produce?

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• If you add 50 g of KCl to 100g of water at 50°C, what type of solution would you produce?

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4. How many grams of KClO₃ must be dissolved in 100g H₂O at 80^oC to be considered a saturated solution?

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5. How many grams of NH₃ must be dissolved in 100g H₂O at 15^oC to be considered a saturated solution?

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6. A beaker containing 130 grams of NaNO₃, in 100 grams of water has a temperature of 10°C. Approximately how many grams of the salt are NOT dissolved on the bottom of the beaker?