AP Chemistry Chapter 10 Notes: Solutions
Background
I.
Solution: a ______________________ mixture
A.
Components of a solution
1.
solute: the substance being _________________
2.
solvent: the substance that _________________
B.
A solution’s properties are the ____________________________ the sample.
C.
Solutions can be _________________________________________.
D.
Liquid solutions:
1.
The solute can be a ________________________________.
2.
The components cannot be separated by ___________________________ but they can be
separated through ________________________ or ______________________.
3.
The components are not large enough to scatter ______________
light.
E.
Ionic solutions can be detected by measuring their _____________________.
Solvation
I.
Solvation - the act of _____________________
II.
How it happens (given that a given substance IS soluble):
A.
A _______________ is placed in solution.
B.
The solvent, by _________________________________, begin to pull off each molecule/ion of the solid.
C.
Solvation will continue until the solute is completely _____________________ OR until the solution is
______________________.
1. Saturated solution: all ______________ particles are associated with ______________ particles.
2. Solubility: Measures the ___________________ amount of solute that can be
_____________________ in an amount of solvent.
III.
Miscibility
A.
Polar solutes are ________________ (________________) in polar solvents.
B.
Nonpolar solutes are _________________________ (_________________________) in polar solvents.
IV.
Solvation has to do with ________________________________.
A.
The __________________ the attraction, the greater the _________________________.
Page 1 of 6
B.
If the force in the solid is _________________ than the attraction to the _________________, the solid
will ___________ dissolve.
C.
Examples:
1.
Predict whether each of the following substances is more likely to dissolve in carbon
tetrachloride (CCl4) or in water: C7H16, Na2SO4, HCl, and I2.
2.
Arrange the following substances in order of
increasing solubility in water:
Solubility Effects
I.
Look at cramsheet.
A.
The _______________ the temperature, the
___________ the solubility of the
__________________________, the
_________________ solubility of ________.
B.
Pressure’s effect on solubility only affects _____________.
1. The __________ the pressure, the __________ the solubility of a gas (can of soda)
2. Henry's Law: relates ____________ to ___________________
3. Equation:
a. Sg = ___________________ of a gas
b. k = Henry's Law _____________ (unique for ________________ in a particular solvent)
c. Pg = ________________________________ of the gas
4. Example: Calculate the concentration of CO2 in a soft drink that is bottled with a partial pressure
of CO2 of 4.0 atm over the liquid at 25°C. The Henry’s law constant for CO2 in water at this
temperature is 3.1 x 10–2 mol/L-atm.
5. Practice: Calculate the concentration of CO2 in a soft drink after the bottle is opened and
equilibrates at 25°C under a CO2 partial pressure of 3.0 x 10–4 atm.
Page 2 of 6
II.
Energetics of solvation
A.
Three processes involved in solvation
1.
Separation of __________________ particles.
2.
Separation of __________________ particles.
3.
New __________________________________ interactions.
B.
Overall enthalpy of solvation is known as the
______________________________________
(________)
1.
Endothermic: overall ∆H is ________________,
feels ___________.
2.
Exothermic: overall ∆H is
__________________, feels __________.
3.
Depends on the _______________________ of
the intermolecular/interparticle interactions
before and after _____________________.
Concentration Units
I.
II.
III.
IV.
See your cramsheet.
___________________ is the most used in AP (equilibrium, kinetics, acid-bases, etc.).
_________________________________ (gases, vapor pressure) is next.
Always be aware of ___________!!! Use dimensional analysis to convert between them.
Colligative Properties
I.
Properties that depend solely on the _______________________ of a substance.
II.
Vapor Pressure Lowering
A.
Adding _________ lower the vapor pressure of a solvent.
B.
Since the solute particles _______________ solvent particles, molecules need more ______________ to
overcome __________________________________________________________________________.
C.
Thus, there are ______________ molecules in the gas phase, __________________ the vapor pressure.
D.
Raoult's Law
1.
Relates solvent ____________________________ to __________________________________.
2.
Equation:
a.
b.
c.
d.
PA = ________________________________ of solvent A at a given temperature
(_________________ is in the ____________________)
XA = ____________________________ of solvent A
P°A = ____________________________ of ____________________________________
at given temp.
In calculating this, always think about the solvent!
Page 3 of 6
3.
____________________ the solute concentration ___________________ the mole fraction of
the solvent, which ______________ vapor pressure.
4.
Example: Calculate the expected vapor pressure at 25°C for a solution prepared by dissolving
97.4 g of common table sugar (sucrose C12H22O11, MW=342) in 453 mL of water. At 25°C the
density of water is approximately 1.00 g/mL and the vapor pressure is 23.76 mm Hg.
III.
Boiling Point Elevation (BPE)
A.
___________________________ attractions affect vapor pressure, changing the
_______________________________!
B.
____________________ the vapor pressure means that it takes ________________________________
to equal atmospheric pressure.
C.
Thus, increasing ______________________________ increases _____________________________.
D.
Note: _________ dissolve into their _____________________________. Example: one mole of NaCl =
_____________________________. Molecular compounds = _______________________ of particles.
IV.
Freezing Point Depression (FPD)
A.
Solute-solvent attractions affect the solvent's
ability to ____________________.
B.
Thus, ___________________________ solute
concentration makes it _____________________
__________________________, decreasing the
solvent’s __________________________________
C.
Note again: 1 mol NaCl = _______moles of ions.
D.
List the following aqueous solutions in order of
their expected freezing point: 0.050M CaCl2, 0.15M
NaCl, 0.10M HCl, 0.050M HC2H3O2, 0.10M
C12H22O11.
Page 4 of 6
V.
Ideal Solutions
A.
In ideal solutions, __________________________________________________________.
B.
In reality, _________________________ interactions are ___________________________________
_________________ (re: ____________________ compounds).
C.
Experimentally, the values deviate from ________________________ solutions.
D.
For example...
E.
This is known as the ________________________________
1.
One mole of NaCl does not yield __________________________________ of ions.
2.
Some ions _________________________________________ with each other.
3.
Thus, the real concentration of ions is a ___________________________________________ the
concentration of NaCl.
4.
____________________________ is more likely at high
_________________________________________
5.
Thus, the higher the _________________________________,
the less ______________ it is.
Separating Solutions
I.
Chromatography: _______________________ a solution
through the chemical attraction between the
________________________ and the ____________________.
A.
Involves a _____________________________ phase
and a ________________ phase.
B.
The final _________________ of the _______________
phase is known as the ___________________________
C.
The position of each component is determined by the Rf value.
1.
2.
The ________________ the Rf value (closer to ______), the
more ____________________ the component is to the
solvent.
Page 5 of 6
II.
Distillation: _______________________ a solution through the different ________________________________
of the components.
A.
B.
C.
Involves _________________ a solution to a temperature that is _____________ the boiling point of the
one component that is to be distilled and _____________ the boiling point of all the other components.
The components with weaker _______________________________ will boil off at a lower temperature.
Sometimes it is performed __________________________ to increase ________________.
Beer’s Law
I.
Relates concentration to how much ________________
_____________________________________________.
II.
Definitions:
A.
Absorbance (A): The relative amount of ___________________________________ by the solution.
Opposite of transmittance.
B.
Line Equation: _________________________. Based on a graph using ______________ concentrations
(_____________________). This will be used to calculate an _______________________ concentration.
C.
Blank: solution with a concentration of 0 (zero) M. Used as a control (b/c water absorbs some light!)
III.
Equation:
Where A = measured _________________________ (no ________________)
a = ___________________________________. Depends on the substance used and the
_____________________________ of light used. Units: _________________________
b = __________________________ in centimeters (width of __________________________)
c = __________________________________________________
IV.
Beer's Law concepts.
A.
B.
C.
The solution measured
______________________________________.
If the points do not give a
___________________________________, Beer's Law
cannot be used.
The ______________________________ must be set
to an optimal ____________________________ for
accurate analysis.
Page 6 of 6