Chapter 13: Properties of Sultions

Question 1

What are the 2 factors affecting the ability of substances to form solutions?

Answer 1

natural tendency for substances to mix | intermolecular interactions

Question 2

How does mixing of gases happen spontaneously?

Answer 2

due to entropy (S)

Question 3

What are the 3 kinds of intermolecular interactions involved in solution formation?

Answer 3

solute-solute interactions | solvent-solvent interactions | solvent-solute interactions

Question 4

What are the solute-solute interactions?

Answer 4

between solute particles = need to overcome them in order to disperse the solute particles within the solvent

Question 5

What are solvent-solvent interactions?

Answer 5

between solvent particles = need to overcome them to make room for the solute particles in between the solvent molecules

Question 6

What are the solute-solvent interactions?

Answer 6

between solute and solvent particles = need to occur as they mix

Question 7

What is solvation?

Answer 7

interaction that occurs when solute is surrounded by solvent molecules

Question 8

What is hydration?

Answer 8

solvation interaction when solvent is H2O

Question 9

What are hydrates?

Answer 9

solid compounds with a defined number of water molecules within the crystal lattice

Question 10

What is crystallization?

Answer 10

when solute particles collide with the surface of a solute solid and reattach

Question 11

What is a saturated solution?

Answer 11

solution that is in equal equilibrium with undissolved solute

Question 12

What is solubility?

Answer 12

MAX amount of solute that can dissolve in a given quantity of solvent to form a saturated solution

Question 13

What is an unsaturated solution?

Answer 13

less solute dissolved than the amount needed to form a saturated solution

Question 14

What is a supersaturated solution?

Answer 14

solvent holding more solute than is normally possible at that temperature | unstable solutions

Question 15

How can crystallization occur with a super saturated solution?

Answer 15

by adding a “seed of crystal” or scratching the side of a flask

Question 16

What are the 3 factors affecting solubility?

Answer 16

solute-solvent interactions | pressure | temperature

Question 17

How does solubility affect solute-solvent interactions?

Answer 17

increase in solubility is due to stronger attractions between solute and solvent molecules

Question 18

What is miscible?

Answer 18

liquids that mix in all proportions

Question 19

What is immiscible?

Answer 19

liquids that don’t mix in one another

Question 20

How does pressure affect the solubility of a gaseous solution?

Answer 20

increase in partial pressure above the solvent = increases solubility of a gas in solvent

Question 21

What is Henry’s Law?

Answer 21

solubility of a gas in a liquid solvent increases in direct proportion to the partial pressure of the gas above the solution

Question 22

How does temperature affect solubility?

Answer 22

increase temp(T) = increase solubility of solids in water BUT decreases solubility of gases in water

Question 23

What is dilute?

Answer 23

small concentration of solute

Question 24

What is concentrated?

Answer 24

large concentration of solute

Question 25

What are ppm (parts per million) and ppb (per billion) used for?

Answer 25

to express concentrations of very dilute solutions

Question 26

What can you use to convert between Molarity and molality?

Answer 26

density

Question 27

What is the difference between molarity and molality?

Answer 27

molaRity = depends on the VOLUME of solution; varies with temp(T) changes | molaLity = depends on MASS of solvent; doesn't vary with temp(T)

Question 28

What are colligative properties of a solution?

Answer 28

depend on the collective effect of the number of solute particles

Question 29

What does "colligative" mean?

Answer 29

"depending on the collection"

Question 30

What are the 4 kinds of colligative properties?

Answer 30

vapor-pressure lowering | boiling-point elevation | freezing-point depression | osmotic pressure

Question 31

What is a non-volatile substance?

Answer 31

no measurable vapor pressure

Question 32

What does Raoult's Law state?

Answer 32

vapor pressure of a volatile solvent above a solution containing a nonvolatile solute is proportional to the solvent's concentration in the solution

Question 33

What is vapor-pressure lowering?

Answer 33

When a nonvolatile solute is added to a volatile pure solvent, the vapor pressure of the solvent (above the resulting solution) is lower than the vapor pressure above the pure solvent.

Question 34

What is boiling-point elevation?

Answer 34

the boiling point of a solution is HIGHER than that of the pure solvent due to vapor-pressure lowering | higher temp is now needed to reach a vapor pressure of 1atm

Question 35

What is freezing-point depression?

Answer 35

freezing point of solution is LOWER than that of the pure solvent due to vapor-pressure lowering | lower temp is now needed to reach a vapor pressure of 1atm

Question 36

What is the van't Hoff factor (i)?

Answer 36

number of fragments that a solute breaks up into for a particular solvent

Question 37

What is the van't Hoff factor for non-electrolytes?

Answer 37

1

Question 38

What is the van't Hoff factor for electrolytes?

Answer 38

depends on how the substance ionizes

Question 39

What is osmosis?

Answer 39

net movement of solvent molecules from low [solute] --> high [solute] (to even things out)

Question 40

What is osmotic pressure?

Answer 40

the pressures that stops osmosis

Question 41

What are the 3 types of of solutions in osmosis?

Answer 41

isotonic | hypertonic | hypotonic

Question 42

What is an isotonic solution?

Answer 42

same osmotic pressure of solvents and solutes = solvent passes through semi-permeable membrane at the same rate both ways

Question 43

What is a hypertonic solution?

Answer 43

high osmotic pressure = solvent enters solution at a higher rate than leaving

Question 44

What is a hypotonic solution?

Answer 44

low osmotic pressure = solvent enters solution at a slower rate than leaving

Question 45

What are colloids?

Answer 45

suspensions of particles larger than individual ions or molecules, but TOO small to be settled out by gravity

Question 46

What is the Tyndall effect?

Answer 46

phenomenon illustrating the ability of colloidal particles to scatter rays of light

Question 47

What regions do colloids have?

Answer 47

hydrophobic and hydrophilic regions