ch 17

Question 1

homogenous mixture

Answer 1

can be any phase
ex. gas/gas

Question 2

solution

Answer 2

solute + solvent

Question 3

colligative properties

Answer 3

physical properties that depend on # of solute particles

1. boiling point elevation
2. freezing point depression
3. osmotic pressure

Question 4

boiling point elevation

Answer 4

when we add a nonvolatile solute to a solution boiling point increases
nonvolatile solutes dont evaporate easily (sits in and above liquid and prevents liquid from turning to gas)

lowers vapor pressure and increases boiling point

Question 5

osmotic pressure

Answer 5

pressure required to stop the flow of solvent from low to high concentration
when osmosis stops, same osmotic pressure = isotonic

pi = iMRT

Question 6

solubility rule

Answer 6

like dissolves like
nonpolar/nonpolar
polar/polar

Question 7

thermodynamics of solute formation

Answer 7

1. expanding solute –> break up and expand –> delta H (+)
2. expand solvent –> (delta H (+)
3. mix solute and solvent usually delta H (-)

Question 8

factors affecting solubility

Answer 8

saturation of soln
temperature
pressure

Question 9

how does saturation affect solunility

Answer 9

saturated = soln holding max # of solute
unsat. = soln holding less than max amount
supersat = soln holding more than max solute

Question 10

how temp afffects solubility

Answer 10

solids : as temp increases solubility increases
gases : as temp increases KE of gas molecules increase and thus they can escape the liquid more, so solubility decreases

Question 11

how does pressure affect solubility

Answer 11

henry’s law
P = kmX (x= mole fractin
when pressure increases. more gas dissolves into liquid

Question 12

vapor pressure

Answer 12

pressure exerted by vapor of a liquid or solid
volatile : high VP, evaporates easily, low BP
nonvolatile: low VP , doesn’t evPORATE easily

Question 13

what happens if you mix a volatile solvent and a nonvolatile solute

Answer 13

BP increases and VP decreases
gas is trapped by solute

Question 14

raoult’s law

Answer 14

Psoln = Xsolvent*Psolvent

only solvent contributes to VP

Question 15

what happens if you mic a volatile and volatile

Answer 15

both contribute to VP

Question 16

deviations from raoult’s law

Answer 16

no interactions: ideal soln. (nonpolar/nonpolar) –> VP as expected delta H = 0

unfavorable interactions–> repulsions–> polar and nonpolar –> VP higher than expected, positive deviation delta H (+)

favorable interactions –> polar and polar –> solution interactions stronger than components interactions –> VP lower than expected, delta H(-)