Solutions and Colligative Properties

Question 1

Molality (m)

Answer 1

moles of solute/kg of solvent

Question 2

Molarity (M)

Answer 2

moles of solute/liters of solution

Question 3

addition of solute

Answer 3

• vapor pressure of liquid decreases
• freezing point of liquid decreases
• boiling point of liquid increases

Question 4

lowest freezing point

Answer 4

most ions when dissociated in water

Question 5

osmotic pressure

Answer 5

=MRT

Question 6

solubility in water: alkali metals

Answer 6

soluble

Question 7

solubility in water: salts of ammonium ion (NH4+)

Answer 7

soluble

Question 8

solubility in water: chlorides, bromides, iodides

Answer 8

soluble except with Ag+, Pb+, and Hg2+2

Question 9

solubility in water: salts of sulfate ion (SO4-2)

Answer 9

soluble except with Ca+2, Sr+2, Ba+2, and Pb+2

Question 10

solubility in water: metal oxides

Answer 10

insoluble except with alkali metals and CaO, SrO, and BaO

Question 11

solubility in water: hydroxides

Answer 11

insoluble except with alkali metals and Ca+2, Sr+2, Ba+2

Question 12

solubility in water: carbonates (CO3-2), phosphates (PO4-2), sulfides (S-2), sulfites (SO3-2)

Answer 12

insoluble except with alkali metals and ammonium

Question 13

solubility product constant (Ksp)

Answer 13

Ksp = [mA+]^m [nB-]^n

for reaction: AmBn(s) –> mA+(aq) + nB-(aq)

Question 14

anhydride

Answer 14

• nonmetals form acid anhydrides

- metals form basic anhydrides

Question 15

specific gravity

Answer 15

• the ratio of the density of a substance in any set of units to the density of water in those same units
• density = m/V

Question 16

Normality (N)

Answer 16

number of gram equivalent weights of solute per liter of solution (number of molecules in a compounds)

Question 17

Normality in a titration

Answer 17

use the Molarity of the compound and multiply it by the number of moles of OH- or H+ (this is the number of moles that will dissociate and contribute to the titration)

Question 18

reduce ion concentration in an aqueous solution

Answer 18

• add a compound that will produce a precipitate with the ion
• which compound is least soluble with the ion that is desired to reduce its concentration?
  ex: AgNO3 would most effectively reduce the chloride ion concentration when added to a saturated aqueous solution of NaCl

Question 19

greatest boiling point given molality’s

Answer 19

• multiply molality by the amount of ions when dissociated

- largest number will have the highest bp