Chapter 12: Solutions


capable of being dissolved


homogeneous mixture of two or more substances combined in a single phase. same composition and properties throughout


dissolving medium in a solution


substance dissolved in a solution. particles are so small they can not be seen by the naked eye. Usually .01 to 1 nm in diameter


solution of two metals


When particles in a solvent are so large they settle out unless the mixture is constantly stirred or agitated. Particles are over 1000 nm in diamter. (e.g. muddy water). Can be filtered


Mixture formed by particles that are intermediate in size between those in solutions and suspensions. Between 1nm and 1000 nm. Particles disperse through the solution. Appear homogeneous, but particles are large enough to scatter light (Tyndall effect) Pa


Substance that dissolves in water to give a solution that conducts electric current. Usually ionic compounds as it separates into ions when dissolved, leaving open space for current to pass through.


Substance that dissolves in water to give a solution that does not conduct an electric current. Contains neutral solute particles, do not separate or are not attracted by solvent molecules

Factors affecting Rate of Dissolution

1) Increasing surface area of solute exposes more solvent to solute, facilitating dissolution
2) Agitating solution (stirring/shaking) helps disperse solute molecules among solvent particles
3) Heating a solvent, increases KE, resulting in more collisions

Why is there a limit to the amount of solute per amount of solvent at given conditions?

When particles dissolve, they can collide with each other and re-form a crystal.

Solution Equilibrium

Physical state in which the opposing processes of dissolution and crystallization of a solute occur at equal rates

Saturated Solution

A solution that contains the maximum amount of dissolved solute at the existing conditions. Falls on the line

Unsaturated solution

A solution that contains less solute than a saturated solution under the existing conditions. Falls below line.

Supersaturated solution

Solution that contains more dissolved solute than a saturated solution contains under the same conditions. If the solution is left to cool undisturbed, sometimes the excess solute does not separate forming supersaturated solution


amount of that substance required to form a saturated solution with a specific amount of solvent at a specified TEMPERATURE. For gases pressure must be specified as well. Rate at which a solid dissolves is unrelated to its solubility at that temperature.

Like Dissolves Like

predicts whether substances will dissolve in another. if they are similar in terms of bonding, polarity, and intermolecular forces - they will dissolve. NOT ALWAYS though


solution process with water as the solvent, usually with ionic compounds.

Crystallization in aqueous solutions

Ionic substances form crystals that incorporate water molecules, called hydrates.

Do ionic compounds dissolve in non-polar solutions?

No; solvent particles do not attract ions in crystal, no force to overcome the crystal.

Immiscible liquids

Not soluble in each other (e.g. toulene and water)


Liquids that dissolve freely in one another in any proportion. Sometimes due to hydrogen bonding between solute and solvent (ethanol and water) or because they are similar in terms of intermolecular forces (oil and carbon tetrachloride)

Effects of pressure on solubility

Do not effect liquid and solids. Increases in pressure increase gas solubilities in liquids. There is more stress on the equilibrium, more collisions, increase in rate of escaping into gas phase, equilibrium restored at higher gas solubility.

Henry's Law

Solubility of a gas in a liquid is directly proportional to the partial pressure of that gas on the surface of the liquid


rapid escape of a gas from a liquid in which it is dissolved in

Effects of temperature on solubility

Increasing temperature decreases gas solubility because more solute molecules can return to the gas phase. Equilibrium is reached with fewer gas molecules.
Usually increasing temperature increases solubility of solids. But in some, same increase in temp c


solute particle surrounded by solvent particles

When a solute molecule is solvated, is energy released or absorbed?


Enthalpy of Solution

Net amount of energy absorbed as heat by the solution when a specific amount of solute dissolves in a solvent.
Negative value indicates energy is released
Positive value indicates energy is absorbed


measure of the amount of solute in a given amount of solvent or solution


number of moles of solute in one liter of solution (amount of solute (mol) / volume of solution (L)).

How do you make a 1M solution?

Add 1 mol of solute in LESS than 1.00 liter of solvent. Then add to make sure total vol is 1 L


Concentration of a solution expressed in moles of solute per kilogram of solvent (amount of A (mol) / mass of solvent (kg) )