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CHEM 162-2007 EXAM I
CHAPTER 12 - PROPERTIES OF SOLUTIONS
•
SOLUTION CONCENTRATIONS CONCEPTS (Molarity, mole fraction, etc.)
•
SOLUTION CONCENTRATIONS CALCULATIONS (Molarity, mole fraction, etc.)
•
ENERGETICS OF SOLUTIONS AND SOLUBILITY CONCEPTS
•
ENERGETICS OF SOLUTIONS AND SOLUBILITY CALCULATIONS
•
VAPOR PRESSURE OF SOLUTIONS CONCEPTS (Henry’s Law, Raoult’s Law)
•
VAPOR PRESSURE OF SOLUTIONS CALCULATIONS
•
COLLIGATIVE PROPERTIES (BOILING POINT, FREEZING POINT, OSMOTIC PRESSURE
CHANGES) CONCEPTS
•
COLLIGATIVE PROPERTIES (BOILING POINT, FREEZING POINT, OSMOTIC PRESSURE
CHANGES) CALCULATIONS
•
MISCELLANEOUS
E. Tavss, PhD
1

FORMULAS
Mass percent = grams of solute/100 g solution
Molarity = moles of solute/L of solution
Molality = moles of solute/kilogram of solvent
PPM = grams of solute/1,000,000 grams solution
Volume percent = volume of solute/100 mL of solution
Proof = 2 x Vol. %; e.g., 2 x 40 mL/100 mL solution = 80 proof
Mole fraction: X
A
= n
A
/(n
A
+ n
B
)
X
A
+ X
B
= 1
Particle fraction:
i
X
A
= in
A
/(in
A
+ in
B
)
i
X
A
+
i
X
B
= 1
Raoult’s law: P
soln
=
i
X
solvent
P
o
solvent
i
X
solvent
= in
solvent
/(in
solvent
+ in
solute
)
i
X
A
+
i
X
B
= 1
P
Total
= P
A
+ P
B
=
i
X
A
P
o
A
+
i
X
B
P
o
B
van’t Hoff factor, “i”; i = moles of particles in solution/moles of solute dissolved
Boiling-point elevation: ΔT = T
f
- T
i
= K
b
im
solute
Freezing-point depression: ΔT = T
f
- T
i
= -K
f
im
solute
(+K
f
gives absolute change in temp; -K
f
gives actual T
f
or T
i
)
Osmotic pressure: πV = inRT
π = (n/V)iRT = iM
solute
RT
ΔH
soln
= ΔH
solute-solutebondbreaking
+ ΔH
solvent-solventbondbreaking
+ ΔH
solute-solventbondforming
ΔH
hydr
=
ΔH
solvent-solventbondbreaking
+ ΔH
solute-solventbondforming
ΔH
soln
= ΔH
solute-solutebondbreaking
+ ΔH
hydr
Henry’s Law: X
A
=kP
A
; X
A
= mole fraction of dissolved gas in solution
2

SOLUTION CONCENTRATIONS CONCEPTS
CHEM 162SG-2001 HOURLY EXAM I
CHAPTER 11 - PROPERTIES OF SOLUTIONS
SOLUTION CONCENTRATIONS CONCEPTS
14.
To 1000 g of water containing 0.010 mole of NaCl, 10.0 g of ethyl alcohol, C
2
H
5
OH(l)
are added. Which quantity remains the same?
A.
the molarity of NaCl
B.
the mass percentage of NaCl
C.
the mole fraction of NaCl
D
.
the molality of NaCl
E.
the vapor pressure of water
CHEM 162-2003 HOURLY EXAM 1 + ANSWERS
CHAPTER 11 - PROPERTIES OF SOLUTIONS
SOLUTION CONCENTRATION CONCEPTS
1.
For which of the following conversions must you know the density of the solution?
A.
mass percent to molality
(g solute/100 g solution) x (mol/g) x 1000 g/kg = molality
B
.
mass percent to molarity
(g solute/100 g solution) x (mol/g) x (g/mL) x (1000 mL/L) = molarity
C.
mole fraction to mass percent
((mol
A
x (g/mol))/(mol
A
x (g/mol) + mol
B
x (g/mol))) x 100 = mass percent
D.
mole fraction to molality
(mol
A
)/(mol
A
x (g/mol) + mol
B
x (g/mol)) x 1000 g/kg = molality
E.
volume percent to proof
mL
solute
/100 mL
solution
x 2 = proof
1.
1

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