chap 11 Flashcards
(25 cards)
define diffusion
net movement of solute or solvent molecules from high concentration to low concentration
define osmosis
diffusion of solvent where eater is solvent. observed when solvent particles are flowing across semipermiable membrane. low solute concentration to high solute concentration so if there’s more solutes on one side of membrane H2O will go to that side.
describe colligative properties of solution
nonvol solutes in a vol solution. monitors how these properties behave due to BP, FP, vapor pressure, and osmotic pressure.
define vaporization
tendency for liquid to go from liquid to gas phase(ex: evaporation, boiling, vaporization)
define evaporation
when vaporization occurs at a temp that is lower than BP at given pressure.
define boiling point
temp at which vapor pressure is equal to the atm pressure. above liquid surface.
formula for osmotic pressure? and what it means
pi symbol= iMRT
where pi sym=P(pressure)
i= van t hoff
M= molarity(mol/L)
R= ideal gas constant- 0.0821
T=temp in K
hypertonic, hypotonic, and isotonic solutions define whole then define each.
solution concentration of the outside environment(nonvol solute particles) relative to the inside. (ex pickle. nonvol part outside so water leaves cucumber)
hypertonic- more solute particles outside so water flows out
isotonic-same concentration inside and out so no net flow
hypotonic-more solute inside so water flows in.
define vapor pressure. and relationship btwn vapor press and volatility
the partial pressure exerted by a gas in equilibrium with its liquid state at a given temperature. the higher the vapor pressure the more volatile a liquid is.
relationship btwn vapor pressure and temperature? when do liquids reach bp?
VP increases with increasing temp. liquids reach BP when VP = atmospheric pressure.
define the boiling point in regards to VP and atm
BP is when VP is equal to atmospheric pressure. you can lower BP via lower atm
what is raoults law? formula?
total VP of an ideal solution of volatile liquids depends on the VP of each component in the solution and its mole fraction in the liquid mixture.
formula: TotalVP= X1P1+X2P2
where X1P1= X-mole fraction and P1-the VP of molecule(torr). to find mole fraction get mol of each molecule add tg and divide orginal mol by the total. IF molecule NONVOL VP is ZERO.
colligative properties of solutions depend on what?
they depend on the concentration of the nonvol solute but NOT their identity.
freezing point depression is what?
nonvol solute particles interfere with the ability of liquid solvent molecules to go into solid phase. (ex why we put salt on roads for snow)
what is molality?
Mols solute/kg solvent
conversions:
1 L —> 1 Kg
what is the van t’ hoff factor?
(i)- moles of nonvol particles in solution per moles of dissolved solute. if NONELECTROLYTE i=1 if ELECTROLYTE i= how many molecules are being dissolved
ex: 1 mol CaCl2–> 1Ca+2 + 2Cl- so 3 mols nonvol particles
formula for BP elevation and FP depression
BP: 🔺️Tf= Kf • i • m
FP: 🔺️Tb= Kb • i • m
where 🔺️Tf/b is change in FP or BP
Kf/b is mol/kg and given
i is van t hoff #
m is molality mol solute/kg solvent
when finding BP and FP what must you do once you get the 🔺️Tf/b?
if FP 0°C - change= FP
if BP 100°C + change= BP
What is the freezing point of automobile radiator fluid prepared by mixing equal
volumes of ethylene glycol (62.07 g/mol) and water at a temperature where the
density of ethylene glycol is 1.114 g/mL and the density of water is 1.000 g/mL?
Kf = 1.86 °C/m
-33.38 C
the experimentally measured freezing point of a 1.90 m aqueous solution of NaCl is -6.57 °C. What is the value of the van ‘t Hoff factor for this solution? Kf = 1.86 °C/m
i= 1.86
The following pairs of aqueous solutions are separated by a semipermeable
membrane. In which direction will the solvent flow?
a = 1.25 M NaCl
A= 1.50 M KCl
b = 3.45 M CaCl2
B= 3.45 M NaBr
c = 4.68 M glucose
C = 3.00 M NaCl
a —-> A
B——>b
c——>C
Calculate the osmotic pressure at 20 °C. 40.0 mL of glycerol (C3H8O3) in 250.0 mL of aqueous solution (density
of glycerol = 1.265 g/mL)
52.92
vapor pressure at 20 °C
cyclohexane (C6H12): 66.9 torr
toluene (C7H8): 21.1 torr
total vapor pressure = 42.0 torr
Calculate the mole fraction of cyclohexane in the liquid phase
0.456
