12.5 – 12.8 Student
Notes
C. Vapor Pressure of a
Solution
1. Vapor
pressure lowering –
2. Raoult’s Law
a. Def
b. Formula
c. Formula
3. Calculating
Vapor-Pressure Lowering
Calculate
the vapor-pressure lowering of water when 5.67 g of glucose, C6H12O6,
is dissolved in 25.2 g of water at 25° C. The vapor pressure of water at 25° C
is 23.8 mm Hg. What is the vapor pressure of the solution?
4.
Fractional
Distillation
D.
Boiling-Point
Elevation and Freezing-Point Depression
1.
Boiling-Point
Elevation
a. Def
b. Formula
2. Freezing-Point
Depression
a. Def
b. Formula
3. Calculating
Boiling-Point Elevation and Freezing-Point Depression
An
aqueous solution is 0.0222 m glucose. What are the boiling point and the
freezing point of this solution?
4. Calculating
the Molecular Weight from Freezing-Point Depresson
Camphor
is a white solid that melts at 179.5° C. It has been used to determine the
molecular weights of organic compounds, because of its unusually large
freezing-point-depression constant (40° C/m), which allows ordinary
thermometers to be used. The organic substance is dissolved in melted camphor,
and then the melting point of the solution is determined.
a. A 1.07 mg
sample of a compound was dissolved in 78.1 mg of camphor. The solution melted
at 176.0° C. What is the molecular weight of the compound?
b. If the
empirical formula of the compound is CH, what is the molecular formula?
E. Osmosis
1. Def –
2. Osmotic
pressure
a. Def
b. Formula
3. Calculating
Osmotic Pressure
The
formula for low-molecular weight starch is (C6H10O5)n, when n averages 2.00 x 102. When
0.798 g of starch is dissolved in 100.0 mL of water
solution, what is the osmotic pressure at 25° C?
E.
Colligative Properties of Ionic Solutions
1.
Freezing-point
lowering
2.
Vapor-pressure
lowering
3.
Boiling-point
elevation
4.
Osmotic pressure