Solutions

Question 1

Solvation involves…

Answer 1

breaking intermolecular interactions between solute molecules and between solvent molecules and forming new intermolecular interactions between solute and solvent molecules together.

Question 2

Solute molecules move…

Answer 2

freely in the solvent and interact with it by way of intermolecular forces such as ion-dipole, dipole-dipole, or hydrogen bonding

Question 3

When interactions between solute and solvent are strong than the original ones…

Answer 3

Solvation is exothermic and the process is favored at low temperatures

Question 4

When the interactions between solute and solvent are weaker than the original ones…

Answer 4

solvation is endothermic and the process is favored at high temperatures.

Question 5

Entropy

Answer 5

the degree to which energy is dispersed throughout a system or the amount of energy distributed from the system to the surroundings at a given temperature

Question 6

When the maximum amount of solute has been added…

Answer 6

the dissolved solute is in equilibrium with its undissolved state, and we say that the solution is saturated.

Both dilute and concentrated solutions are NOT saturated

Question 7

Solubility Rule 1

Answer 7

All salts containing ammonium and alkali metal (grp 1) cations are water-soluble

Question 8

Solubility Rule 2

Answer 8

All salts containing nitrate and acetate anions are water-soluble

Question 9

Chelation

Answer 9

The central cation can be bonded to the same ligand in multiple places.

Used to sequester toxic metals

Question 10

Percent composition by mass

Answer 10

Mass of solute/ mass of solution x 100%

Question 11

Mole fraction

Answer 11

moles of A / total moles of all species

* sum of mole fractions in a system will always equal one

Question 12

Molarity

Answer 12

moles of solute / liters of solution

Question 13

molality

Answer 13

moles of solute / kg of solvent

Question 14

Normality

Answer 14

molarity of the stuff of interest in the reaction

Question 15

Concentration of a solution after dilution can be determined using:

Answer 15

M1V₁ = M₂V₂

M: molarity

V: volume

Question 16

K_sp

Answer 16

Solubility equilibrium constant for a saturated solution of an ionic compound.

K_sp = [Ag][Cl]

When temperature increases, Ksp increases for non-gas solutes and decreases for gas solutes

Question 17

Ion product (IP)

Answer 17

Used to determine where a system is in relation to equilibrium position.

IP < Ksp : unsaturated, solute with continue to dissolve

IP = Ksp : saturated, solution is at equilibrium

IP > Ksp : supersaturated, precipitation will occur

Question 18

K_f (formation constant)

Answer 18

Equilibrium constant for the formation of a complex ion. Typically is larger than K_sp.

Uses products (ions) from dissolution of original solution.

Question 19

Common ion effect

Answer 19

Reduction in solubility of a substance due to presence of common ions in solution.

Question 20

Vapor pressure depression

Answer 20

As solute is added to a solvent, the vapor pressure of the solvent decreases proportionately (Raoult’s Law)

• A higher temperature will be required to match the atmospheric pressure, thereby raising the boiling temperature.

PA = X_A P°_A

P_A = VP of solvent A w/ solutes

X_A = Mole fraction of solvent A

P°_A = VP of pure solvent

Question 21

Freezing point depression

Answer 21

Presence of more solutes will lower the freezing point of the solution relative to the original solvent.

Question 22

Osmotic Pressure

Answer 22

Sucking power generated by solutions in which water is drawn into a solution. Water moves in direction of high solute concentration.

Question 23

The solubility of gases…

Answer 23

is directly proportional to the atmospheric pressure.