Solutions & Solubility

- solution: a homogeneous mixture

- solvent: substance that has another substance dissolved in it

- solute: substance that is dissolved

- solubility: amount of solute that dissolves in a given quantity of solvent

Factors Affecting Solubility

I. nature of the solute & solvent

a) Covalent Compounds

- polar solutes dissolve in polar solvents (e.g.- sugar in water), nonpolar solutes dissolve in nonpolar solvents (e.g.- iodine in kerosene)

- small, polar molecules dissolve best in water (see Table 8.2 on p. 295)

b) Ionic Compounds

- ionic compounds usually dissolve in water, but those consisting of small ions and/or ions with large charges don’t (see Solubility

Guidelines on p. 334)

II. temperature

- when solids dissolve in liquids, solubility usually increases with temperature (e.g.- more sugar can dissolve in a cup of hot water than a cup of cold water)

- when gases (such as O2 or CO2) dissolve in water, the reverse is true

thermal pollution

carbonated beverages

III. pressure

- solubility of a gas in a liquid increases with pressure (e.g.- carbonated beverages, the “bends”)