Solubility • Def.: the maximum amount of solute that will dissolve in a given amount of solvent AT a specified temperature and pressure. (expressed in g solute/100 g solvent) • Example: g sugar/100 g water • What happens to the excess solute if you add more than the maximum? • Table 15-2, p457
Solubility, continued…. • Solubility at the particle level: • As more solute particles are added to the solvent, there are fewer solvent particles to surround the added solute particles. • As the solute particles move around, some will bump into the undissolved particles and will be “attracted” back to join the solid crystal solute particles.
Solubility, continued…. • Define: • Saturated solution • Supersaturated solution • Factors that affect solubility: • Pressure --- only affects solubility of gaseous solutes and gaseous solutions • Temperature --- HOW???
Solubility, continued…. • Supersaturated solutions (solns) are formed when a solution is saturated at a higher temperature, and then cooled. • http://www.youtube.com/watch?v=XSGvy2FPfCw&safety_mode=true&persist_safety_mode=1 • Real-world use: Rock candy
Solubility, continued…. • The solubility of a gas in any solvent increases as its external pressure (the pressure above the solution) increases. (Think carbonated sodas!) • Henry’s Law: At a given temperature, the solubility (S) of a gas in a liquid is directly proportional to the pressure (P) of the gas above the liquid. • How would you write Henry’s Law in an equation?
Assignment • Practice Problems: p.461 (1-2) • Section Assessment: p.461 (7)