Types of Solutions
Solution: homogeneous mixture made up of a solvent and a solute
Solvent: solution component in which one or more solutes is dissolved.
Usually the solvent is present in greater amounts than the solutes and determines the state of matter in which the solution exists.
Note: Solutions may be one of three phases: solid, liquid or gas
Solute: the solution component that is dissolved in the solvent.
A solution may have several solutes, with the solutes generally present in lesser amounts than the solvent.
Unsaturated Solution: solution that contains less than the maximum quantity of solute that the solvent is able to dissolve at a particular set of conditions.
Saturated Solution: solution that contains the maximum quantity of solute that is normally possible at a given temperature.
Supersaturated Solution: contains more solute than normally expected for a saturated solution.
Saturated solutions are normally prepared by starting with a saturated solution, heating it to a temperature where more solute can be dissolved, and then slowly letting it cool to the original temperature.
Note: For example, a solution of NaCl (table salt; the solute) in water (the solvent) has been prepared, but we are unsure if it is unsaturated, saturated, or supersaturated. We can distinguish between these three types of solutions by addition of a seed crystal (a single crystal of the solute, NaCl)
 If the seed crystal dissolves, the solution is unsaturated.
 If the seed crystal does not dissolve the solution is saturated.
 If the seed crystal does not dissolve, and the excess solute recrystallizes (comes out of solution) the solution is supersaturated.
Alloys: a mixture of two or more metals; a solid solution

Amalgams: metal alloys containing mercury; most are in the liquid phase.
Miscible: two liquids are miscible if they form a solution upon mixing; that is no layers are present.
Example: Water and vinegar are miscible.
Immiscible: two liquids are immiscible if they do not form a solution upon mixing; that is, the liquids form layers.
Example: Water and oil are immiscible.
 Miscibility and solubility depend on the intermolecular attractive forces between the solute particles and the solvent particles.
 You can use the general rule "Like dissolves like" when deciding if two liquids will be miscible or immiscible.
 Polar solutes dissolve in polar solvents; nonpolar solutes dissolve in nonpolar solvents; liquid polar solutes and liquid nonpolar solvents are immiscible, as are nonpolar solutes with polar solvents.
Example: Water and vinegar are both polar; they are miscible.
Water is polar and oil is nonpolar; they are immiscible.

Factors Affecting Solubility
Solubility: the concentration of a saturated solution; can be expressed in numerous ways, such as the maximum moles of solute that can be dissolved in a volume of solvent, or the maximum mass of solute that can homogeneously mix with a mass of solvent.
 In general, the solubility of gases in liquids decreases with increasing temperature.
 The solubility of a gas in liquid increases when the gas pressure above the liquid is increased.
 In general the solubility of solids in liquids increases with increasing temperature.

 All ionic compounds dissolve in water to some extent, though this may be very slight.
 For practical purposes a compound is considered to be insoluble if the maximum amount that can be dissolved is less than approximately 0.01 mol/L.
 The following table can be used to determine if an ionic compound is soluble.
Example: NaOH is soluble in H
2
O, but Al(OH)
3
is insoluble.
Is LiCH
3
COO soluble in H
2
O?
Is CaCO
3
soluble in H
2
O?

Concentration of Solutions
Standard Solution: A solution that contains a precise mass of solute in a precise volume of solution
Concentration: refers to the composition of a solution
 One method for expressing concentration is molarity
Molarity (
M
): the number of moles of solute dissolved in one litre of solution; expressed in units of (mol/L)
Note: Often, the unit (mol/L) is abbreviated (
M
).
 Molarity can be calculated from
M
= n
V solute solution
 From this equation we can see that when the volume of solution increases, but the amount of solute remains the same, the concentration decreases; the solution is diluted.
 Note however, that the number of moles present before and after dilution remains the same.
 This leads us to the solution dilution formula
C i
V i
= C f
V f
Where C i
= Initial Concentration (mol/L)
V i
= Initial Solution Volume (L)
C f
= Final Concentration; Concentration after dilution (mol/L)
V f
= Final Solution Volume; Volume of solution after dilution (L)

Percent by Mass and PPM
 One method for expressing concentration is molarity
 Other methods can be used to express the concentration of a solution
Percent by Mass (Mass/Mass)
If you dissolve 5.00 g of NaCl in 95.0 g of H
2
O you get 100.0 g of solution that is 5.00 % NaCl, by mass.
Mass Percent (mass/mass) = Mass solute (g) x 100%
Mass solution (g)
Percent by Mass (Mass/Volume)
If you dissolve 0.9 g of NaCl in 100.0 mL of solution, your solution is 0.9 %
NaCl (mass/volume).
Mass Percent (mass/volume) = Mass solute (g) x 100 %
Volume Solution (mL)
Percent by Mass (Volume/Volume)
If you prepare 100.0 mL of aqueous solution containing 25.0 mL of CH
3
OH
(l) the solution is 25.0 % CH
3
OH, by volume.
Mass Percent (volume/volume) = Volume solute (mL) x 100%
Volume solution (mL)
Parts Per Million (Mass/Mass)
If you dissolve 0.5 g of NaCl in 99.5 g of H
2 that is 5000 ppm NaCl (mass/mass).
O you get 100.0 g of solution
Parts Per Million (ppm) = Mass solute (g) x 10
Mass solution (g)
6

Parts Per Million (Mass/Volume)
If you dissolve 0.9 g of NaCl in 100.0 mL of solution, your solution is 9000 ppm NaCl (mass/volume).
Parts Per Million (ppm) = Mass solute (g) x 10
Volume Solution (mL)
6

Ion Concentrations
 Ionic substances dissociate into ions when dissolved in water.
 The concentration of the ions may be calculated.
 Some molecular substances dissociate when dissolved in water.
 These are primarily acids, that dissociate into H + ions, and a conjugate base.