13.1 Solution Formation and Solubility
1) Separation of solute particles (breaking attractive forces -- endothermic)
2) Separation of solvent particles (breaking attractive forces -- endothermic)
3) Attractive forces formed between solute and solvent particles (exothermic)
Solubility - the maximum amount of a solute that can be dissolved in a solvent
“Like dissolves like” in terms of polarity
To be soluble the attractive forces formed between solute and solvent have to be comparable to those broken in the solute and solvent.
Entropy of Mixing – mixing typically involves an increase in entropy
Miscible – when two liquids mix in all proportions
Immiscible – when two liquids don’t dissolve in one another; they generally form separate layers of liquid
Saturated – when the maximum amount of a solute is dissolved in a solvent
Unsaturated – when less than the maximum amount of a solute is dissolved in a solvent
Supersaturated – when more than the maximum amount of a solute is dissolved in a solvent
Colloid – A homogeneous suspension of particles composed of many atoms/molecules that doesn’t settle out of solution due to gravity. It can’t be separated by filtration or centrifugation.
Factors Affecting Solubility | Solubility of Gases
1) Gases are more soluble at lower temperatures.
2) Gases are more soluble at higher pressures.
What is the solubility of O2 in water at 25°C at sea level? (PO2 = 0.21atm, KH = 1.3×10-3M/atm at 25°C)
Solubility of Ionic Compounds
Most ionic compounds (salts) are more soluble at higher temperatures.