Honors Chemistry
Unit 6 Study Guide
Page 1 of 2
Liquids and Solids
• If the temperature of a liquid-vapor system at equilibrium is reduced, the concentration of the vapor will
decrease and the vapor pressure will decrease.
• If the temperature of a liquid-vapor system at equilibrium is increased, the concentration of the vapor will
increase and the vapor pressure will increase.
• As the atmospheric pressure on the surface of a liquid decreases, its boiling point decreases.
• Molten ionic compounds, such as NaCl, is conduct electricity.
• A phase diagram indicates the conditions under which the various states of a substance exist.
• The triple point of a substance is the temperature and pressure conditions at which states of a substance
coexist at equilibrium.
• Above the critical temperature, a substance cannot exist in the liquid state.
• The lowest pressure under which a substance can exist as a liquid at the critical temperature is the critical
pressure.
Pressure
Critical
Pressure
Melting
Critical
Point
Freezing
Condensation
Vaporization
Liquid
Atmospheric
Pressure
Solid
Sublimation
Triple
Point
Deposition
Freezing
Point
Gas
Boiling
Point
Critical
Temperature
Temperature
Solutions
• A substance whose water solution conducts a current is an electrolyte.
• To conduct electricity, a solution must contain ions.
• A substance whose water solution does NOT conduct a current is a nonelectrolyte.
• Molecules whose water solutions conduct current ionize in water.
• In the expression like dissolves like, the word like refers to similarity in molecular polarity.
• The rule like dissolves like is used to predict solubility.
• A substance that is NOT soluble in a polar solvent is nonpolar.
• Two immiscible substances, such as benzene and water, do not mix together.
Honors Chemistry
•
•
•
•
•
Unit 6 Study Guide
Page 2 of 2
The dissolution of gases in liquids is generally exothermic.
Pressure has the greatest effect on the solubility of gases in liquids.
The solubility of gases in liquids always increases with increasing pressure.
Molarity, molality, and percent composition by mass all are expressions of concentration.
Equations:
• Molarity:
M = n/V
M = molarity (mol/L), n = mols solute, V = volume solution
n = MV
V = n/M
Molality:
•
m = n/m
m = molality (mol/kg), n = mols solute, m = mass solvent (kg)
n = mm
m = n/m
Ions in Aqueous Solutions and Colligative Properties
• Colligative properties depend on the concentration of the solute particles.
• Colligative properties include vapor-pressure lowering, boiling point elevation, freezing point depression,
and osmotic pressure.
• Nonvolatile solutes depress freezing point and elevate boiling point.
• Equations:
• For freezing point depression:
• ∆Tf = Kfm
• Where ∆Tf is the change in freezing point, Kf is the freezing point constant and m is molality.
• For boiling point elevation:
• ∆Tb = Kbm
• Where ∆Tb is the change in boiling point, Kb is the boiling point constant and m is molality.
Acids and Bases
• An Arrhenius acid is a compound that increases the concentration of hydrogen ions in aqueous solution.
• An Arrhenius base is a compound that increases the concentration of hydroxide ions in aqueous solution
• A Brønsted-Lowry acid is a proton donor. A Brønsted-Lowry base is a proton acceptor.
• A conjugate base is the species that remains after an acid has given up a proton.
• A conjugate acid is the species that is formed by the addition of a proton to a base.
• A Lewis acid is an electron-pair acceptor. A Lewis base is an electron-pair donor.
• When an acid and a base combine, a salt (the cation of the base and the anion of the acid) and water are
formed.
• Water will self ionize.
• The product of the concentrations of H3O+ and OH− is [H3O+][OH−] = 1.00×10−14.
• [H3O+] = (1.00×10−14)/[OH−]
• [OH−] = (1.00×10−14)/[H3O+]
• The pH of an aqueous system usually varies from about 0 (very acidic) to 7 (neutral) to 14 (very basic).
• pH = −log[H3O+]
• [H+] = 10−pH
• Strong acids and bases are strong electrolytes and weak acids and bases are weak electrolytes.
• During a titration, the end point occurs when the [H+] from the titrating acid is equal to the [OH−] from the
titrating base.