Solutions Homogeneous mixture = solution Solute the substance that’s being dissolved Solvent - the substance that the solute is dissolved in.

Types Gas/gas Gas/liquid Liquid/liquid Solid/liquid Solid/solid Air is 78% N 2 and 21% O 2 Carbonated sodas are made by dissolving CO 2 gas in water 8 carat gold is a solid solution of Cu, Ag and Au Vinegar is 5% acetic acid, 95% water Sports drinks are 0.1% NaCl, 5% sugar and 99% water. Examples

How do substances dissolve? If a gas/gas solution is being made: The separate gases move around until they are evenly mixed. Remember that particles in a gas phase do not interact with each other. mixedunmixed

If a solid/solid solution is being made: The solids have to be heated up to a liquid state OR left in contact long enough for the particles to mix. Remember that particles in a solid phase can only vibrate about in a fixed position…it takes a REALLY long time for them to shift position.

If the solvent is a liquid: The solvent molecules surround the solute molecules at the surface and pull them away into the solution. NaCl dissolution

How much will dissolve? Saturated solution: If no more of the solute will dissolve. No more solute will dissolve. Unsaturated solution: Haven’t added enough solute to the solvent for the solution to be saturated. If more solute is added, it will dissolve. Supersaturated solution: Have ‘tricked’ the solution so that there is more solute dissolved in the solvent than is present in a saturated solution. Adding more solute causes the excess solute to precipitate out of solution.

Solubility curves Plots the MAXIMUM number of grams of a solute that will dissolve in 100 g of the solvent at particular temperatures.

Temperature effects If the solute is a liquid or a solid, solubility increases as temperature increases. TemperatureSolubility as

If the solute is a gas, solubility decreases as temperature increases. Temperature effects TemperatureSolubility as

Particles in solution If an ionic compound is used as the solute, it will break up into its ions. NaCl (s) Na +1 (aq) + Cl -1 (aq) MgCl 2 (s) Mg +2 (aq) + 2 Cl -1 (aq) AlCl 3 (s) Al +3 (aq) + 3 Cl -1 (aq) Notice how the subscripts in the formula for the solid become coefficients for the ions.

Definitions: Electrolytes: solutions in which the solutes are ions. Electrolyte solutions will conduct electricity. Nonelectrolytes: solutions in which the solutes are molecules and NOT ions. Nonelectrolytes will NOT conduct electricity. Colligative properties: properties of solutions that depend only on the NUMBER of solute particles present.

Colligative properties Freezing point depression: The normal freezing point of the solvent decreases as the number of solute particles increases. Example: antifreeze Boiling point elevation: The normal boiling point of the solvent increases as the number of solute particles increases. Example: engine coolant Freezing point Boiling point

Which solute would cause the greatest freezing point depression? A) 1 g of NaClB) 2 g of NaCl C) 3 g of NaClD) 4 g of NaCl Equivalent amounts of: A) NaClB) MgCl 2 C) KClD) AlCl 3 Equivalent amounts of: A) a nonelectrolyteB) MgCl 2 C) KClD) NaCl