Ch. 9: Solutions

Question 1

Solutions

Answer 1

Homogeneous mixtures composed of 2 or more substances

- Combine to form a single phase, generally liquid phase

Question 2

Dissolution/Solvation

Answer 2

Solvent particles surround solute particles via electrostatic interactions in this process. Mose dissolutions are endothermic, although the dissolution of gas into liquid are exothermic

Question 3

Solubility

Answer 3

Maximum amt of a solute that can be dissolved in a given solvent @ a given temp– often expressed as molar solubility

Question 4

Molar solubility

Answer 4

The molarity of the solute @ saturation

Question 5

Complex ions/Coordination compounds

Answer 5

Composed of metallic ions bonded to various neutral compounds and anions, referred to as ligands

Question 6

Complex Ions

Answer 6

Formation of complex ions increases the solubility of otherwise insoluble ions (opposite of common ion effect)

Question 7

Coordinate Covalent Bonding

Answer 7

The process of forming a complex ion involves electron pair donors and electron pair acceptors such as those seen in coordinate covalent bonding

Question 8

Percent Composition by Mass

Answer 8

Mass of solute per mass of solution times 100%; used for aqueous solutions and solid-in-solid solutions

Question 9

Mole Fraction

Answer 9

Moles of solute per total moles; used for calculating vapor pressure depression and partial pressures of gases in a system

Question 10

Molarity

Answer 10

Moles of solute per liters of solution; most common unit for concentration and is used for rate laws, the law of mass action, osmotic pressure, pH and pOH, and the Nernst eqn

Question 11

Molality

Answer 11

Moles of solute per kilogram of solvent; used for boiling point elevation and freezing pt depression

Question 12

Normality

Answer 12

Number of equivalents per liters of solution; used for acid-base and oxidation-reduction rxns

Question 13

Saturated solutions

Answer 13

Saturated solutions are in equilibrium at that particular temp

Question 14

Solubility Product Constant (Ksp)

Answer 14

Simply the equilibrium constant for a dissociation rxn

Question 15

Ion Product (IP) to Ksp

Answer 15

Comparison determines the level of saturation and behavior of the soln:
- IPKsp: the solution is supersaturated, and a precipitate will form

Question 16

Formation of a complex ion

Answer 16

Greatly increases solubility

Question 17

Formation or stability constant (Kf)

Answer 17

The equilibrium constant for complex formation. Its value is usually much greater than Ksp

Question 18

Formation of a complex

Answer 18

Increases the solubility of other salts containing the same ions bc it uses up the products of those dissolution rxns, shifting the equilibrium to the right (the opp of the common ion effect)

Question 19

Common ion effect

Answer 19

Decreases the solubility of a compound in a soln that already contains one of the ions in the compound. The presence of that ion in soln shifts the dissolution rxn to the left, decreasing its dissociation

Question 20

Colligative properties

Answer 20

Physical properties of solns that depend on the concentration of dissolved particles but not on their chemical identity

Question 21

Vapor Pressure Depression

Answer 21

Follows Raoult’s law

• The presence of other solutes decreases the evaporation rate of a solvent without affecting its condensation rate, thus decreasing its vapor pressure.
• Vapor pressure depression also explains boiling pt elevation– as the vapor pressure decreases, the temp (energy) required to boil the liquid must be raised

Question 22

Freezing point depression and boiling point elevation

Answer 22

Shifts in the phase equilibria dependent on the molality of the soln

Question 23

Osmotic Pressure

Answer 23

Primarily dependent on the molarity of the solution

Question 24

van’t Hoff factor (i)

Answer 24

For solutes that dissociate, used in freezing pt depression, boiling pt elevation, and osmotic pressure calculations