Solutions. Soluble : solute dissolves in solvent Insoluble: solute will not dissolve in solvent Solubility : amount of solid solute that dissolves in given quantity of solvent at specific temperature/ pressure Miscible : two liquids dissolve in one another/no separation of layers
Insoluble: solute will not dissolve in solvent
Solubility: amount of solid solute that dissolves in given quantity of solvent at specific temperature/ pressure
Miscible: two liquids dissolve in one another/no separation of layers
Immiscible: two liquids do not dissolve in one another/separation of layers
Polar water/ions attract each other
Solvated solute particles collide increasingly with remaining crystal and rejoin crystal
Solvation rate > crystallization rate = continuing solvation
When solvation rate = crystallization rate = dynamicequilibrium
P1 = 150 mm Hg
C1 = 0.44 g O2 /100 mL solution (C is being used as concentration instead of solubility)
P2 = 56 mm Hg
C2 = ?
C2 = 0.15 g O2 /100 mL solution
If 0.85 g of a gas at 4.0 atm of pressure dissolves in 1.0 L of water at 23oC, how much will dissolve in 1.0 L of water at 1.0 atm of pressure and the same temperature?
0.85/4.0 = S2/1.0 S2 = 0.21 g/L
If 0.55 g of a gas dissolves in 1.0 L of water at 20.0 kPa of pressure, how much will dissolve at 110.0 kPa of pressure?
Read 15.1, pp. 452-461
Q pg. 484, #52, 53, 64, 66, 67
Measure of how much solute is dissolved in a specific amount of solvent or solution
3.6 g NaCl
103.6 g NaCl + H2O x 100 = 3.5%
4 scoops of powderTo make ice tea of "normal" strength = ----------------------- 2 quarts of water
8 scoops of powder 4 scoops of powder
---------------------------- or ----------------------------- 2 quarts of water 1 quart of water
Molarity definition based on volume of solution
Molality definition does not have volume in it
Very useful concentration unit in colligative properties
Read 15.2, pp. 462-470
Q pg. 470, #29, 32
Q pg. 484-485, #54, 55, 80, 82, 83a, 84, 85
Depend only on # dissolved particles in solution and not their identity
Depend on identity of dissolved species and solvent
SolubilitySolutes affect some of the physical properties of their solvents
Surface molecules gain enough energy to break free of liquid's intermolecular forces
Gaseous molecules coming into contact w/surface of liquid trapped by those intermolecular forces
When rate of escape = rate of capture, constant, equilibrium vapor pressure above pure liquid formed
http://college.hmco.com/chemistry/shared/media/animations/vapor_pressure_low_a.htmlVapor Pressure Lowering
Write the dissociation equation for Ca3(PO4) 2
Ca3(PO4) 2 + H2O 3Ca+2(aq) + 2PO4-3(aq)
Calculate the i factor
i = 3 + 2 / 1 = 5
Calculate BP of solvent in solution.
∆Tb = Tb - 100 = i Kb m
Tb - 100 = (5)(0.512)(.0222) = 0.0568
Tb = 100 + .0568 = 100.0568 C
1. Which ice cube melted faster? Explain.
2. Why did the string freeze to the ice cube after salt was added, but did not freeze to the cube in which no salt was added?
3. Some people prefer to make their own ice cream. When doing so, they mix the cream in a container that rests within another container tht they fill with water, ice, and salt. Explain the purpose of that outer tub.
4. The freezing point of water decreases as salt is added until it reaches the limit of sodium chloride solubility at -21oC. What are the molarity and molality of the solution at this temperature?
Read 18.3, pp. 471-475
Q pg. 475, #38, 39, 41
Q pp. 484-485, #57, 58, 86, 88
CuSO4 + 5H2O(s) CuSO4(s) + 5H2O(g)
Hydrated (white) anhydrous (blue)
Desiccants absorb moisture from air but remain in solid state (drying agent)
Anhydrous silica gel common one
Deliquescents absorb moisture and form liquid sol
Read 15.4, pp. 476-482
Q pg. 479, #46
Q pg. 484, #60, 63,
Test practice, pg. 487, all questions
Use link for quiz and submit as before.