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![Page 1: © University of South Carolina Board of Trustees Adding a nonvolatile solute to a pure solvent causes: lower vapor pressure P = - P x sol higher.](https://reader031.fdocuments.in/reader031/viewer/2022032723/56649cff5503460f949d0014/html5/thumbnails/1.jpg)
© University of South Carolina Board of Trustees
Adding a nonvolatile solute to a pure solvent causes:
lower vapor pressure DP = - P x csol
higher boiling point DT = +kb x msol
lower freezing point DT = - kf x msol
osmotic pressure
Colligative Properties
![Page 2: © University of South Carolina Board of Trustees Adding a nonvolatile solute to a pure solvent causes: lower vapor pressure P = - P x sol higher.](https://reader031.fdocuments.in/reader031/viewer/2022032723/56649cff5503460f949d0014/html5/thumbnails/2.jpg)
© University of South Carolina Board of Trustees
Adding a nonvolatile solute to a pure solvent causes:
lower vapor pressure DP = - P x csolute
higher boiling point DT = +kb x msolute
lower freezing point DT = - kf x msolute
osmotic pressure
Colligative Properties
![Page 3: © University of South Carolina Board of Trustees Adding a nonvolatile solute to a pure solvent causes: lower vapor pressure P = - P x sol higher.](https://reader031.fdocuments.in/reader031/viewer/2022032723/56649cff5503460f949d0014/html5/thumbnails/3.jpg)
© University of South Carolina Board of Trustees
● Solvent flow initially in balance.
● Adding solute blocks flow right left.
![Page 4: © University of South Carolina Board of Trustees Adding a nonvolatile solute to a pure solvent causes: lower vapor pressure P = - P x sol higher.](https://reader031.fdocuments.in/reader031/viewer/2022032723/56649cff5503460f949d0014/html5/thumbnails/4.jpg)
© University of South Carolina Board of Trustees
● The solvent level on the right rises due to osmotic pressure.
![Page 5: © University of South Carolina Board of Trustees Adding a nonvolatile solute to a pure solvent causes: lower vapor pressure P = - P x sol higher.](https://reader031.fdocuments.in/reader031/viewer/2022032723/56649cff5503460f949d0014/html5/thumbnails/5.jpg)
© University of South Carolina Board of Trustees
● External pressure can restore equilibrium.
P
![Page 6: © University of South Carolina Board of Trustees Adding a nonvolatile solute to a pure solvent causes: lower vapor pressure P = - P x sol higher.](https://reader031.fdocuments.in/reader031/viewer/2022032723/56649cff5503460f949d0014/html5/thumbnails/6.jpg)
© University of South Carolina Board of Trustees
Adding a nonvolatile solute to a pure solvent causes:
lower vapor pressure DP = - P x csol
higher boiling point DT = +kb x msol
lower freezing point DT = - kf x msol
osmotic pressure P = RT x Msol
Colligative Properties
![Page 7: © University of South Carolina Board of Trustees Adding a nonvolatile solute to a pure solvent causes: lower vapor pressure P = - P x sol higher.](https://reader031.fdocuments.in/reader031/viewer/2022032723/56649cff5503460f949d0014/html5/thumbnails/7.jpg)
© University of South Carolina Board of Trustees
Adding a nonvolatile solute to a pure solvent causes:
lower vapor pressure DP = - P x csol
higher boiling point DT = +kb x msol
lower freezing point DT = - kf x msol
osmotic pressure P = RT x Msol
Colligative Properties
moles of solute
Solvent properties
Each can measure molecular mass
![Page 8: © University of South Carolina Board of Trustees Adding a nonvolatile solute to a pure solvent causes: lower vapor pressure P = - P x sol higher.](https://reader031.fdocuments.in/reader031/viewer/2022032723/56649cff5503460f949d0014/html5/thumbnails/8.jpg)
© University of South Carolina Board of Trustees
Last Lecture
Find the molar mass of a solute, if a solution of 1.33 g of the compound dissolved in 25.0 g of benzene has a boiling point of 81.22 oC.
SolventTb
(oC)kb
(oC/molal)
Aceticacid
117.90 3.07
Benzene 80.10 2.53
Water 100.0 0.512
![Page 9: © University of South Carolina Board of Trustees Adding a nonvolatile solute to a pure solvent causes: lower vapor pressure P = - P x sol higher.](https://reader031.fdocuments.in/reader031/viewer/2022032723/56649cff5503460f949d0014/html5/thumbnails/9.jpg)
© University of South Carolina Board of Trustees
Student Example: Molar Mass by Osmotic Pressure
A 5.70 mg sample of protein is dissolved in water to give 1.00 mL of solution. Calculate the molar mass of the protein, if the solution has an osmotic pressure of 6.52 Torr at 20 C.
R = 0.0821 L-atm/K-mol
1 atm = 760 Torr
![Page 10: © University of South Carolina Board of Trustees Adding a nonvolatile solute to a pure solvent causes: lower vapor pressure P = - P x sol higher.](https://reader031.fdocuments.in/reader031/viewer/2022032723/56649cff5503460f949d0014/html5/thumbnails/10.jpg)
© University of South Carolina Board of Trustees
Chapt. 12Solutions
Sec. 5Colligative Properties
with Ions
![Page 11: © University of South Carolina Board of Trustees Adding a nonvolatile solute to a pure solvent causes: lower vapor pressure P = - P x sol higher.](https://reader031.fdocuments.in/reader031/viewer/2022032723/56649cff5503460f949d0014/html5/thumbnails/11.jpg)
© University of South Carolina Board of Trustees
Ions and Colligative Properties
NaCl(s) Na+(aq) + Cl-(aq)
Ca(NO3)2(s) Ca2+(aq) + 2 NO3
-(aq)
nsolute = i nformulafound by
colligative propertiesusually desired
van’t Hoff factor
1 mole byformula wt.
2 moles ofsolute i = 2
1 mole byformula wt.
3 moles ofsolute i = 3
![Page 12: © University of South Carolina Board of Trustees Adding a nonvolatile solute to a pure solvent causes: lower vapor pressure P = - P x sol higher.](https://reader031.fdocuments.in/reader031/viewer/2022032723/56649cff5503460f949d0014/html5/thumbnails/12.jpg)
© University of South Carolina Board of Trustees
Student Example
Arrange the following aqueous solutions in order of
increasing boiling points:
0.03 molal urea(s) (a nonelectrolyte)
0.01 molal NaOH
0.02 molal BaCl2
0.01 molal Fe(NO3)3
![Page 13: © University of South Carolina Board of Trustees Adding a nonvolatile solute to a pure solvent causes: lower vapor pressure P = - P x sol higher.](https://reader031.fdocuments.in/reader031/viewer/2022032723/56649cff5503460f949d0014/html5/thumbnails/13.jpg)
© University of South Carolina Board of Trustees
Student Example
Arrange the following aqueous solutions in order of
increasing boiling points:
0.03 molal urea(s) urea(aq) 0.03 m solute
0.01 molal NaOH
0.02 molal BaCl2
0.01 molal Fe(NO3)3
![Page 14: © University of South Carolina Board of Trustees Adding a nonvolatile solute to a pure solvent causes: lower vapor pressure P = - P x sol higher.](https://reader031.fdocuments.in/reader031/viewer/2022032723/56649cff5503460f949d0014/html5/thumbnails/14.jpg)
© University of South Carolina Board of Trustees
Student Example
Arrange the following aqueous solutions in order of
increasing boiling points:
0.03 molal urea(s) urea(aq) 0.03 m solute
0.01 molal NaOH Na+ + OH- 0.02 m ions
0.02 molal BaCl2
0.01 molal Fe(NO3)3
![Page 15: © University of South Carolina Board of Trustees Adding a nonvolatile solute to a pure solvent causes: lower vapor pressure P = - P x sol higher.](https://reader031.fdocuments.in/reader031/viewer/2022032723/56649cff5503460f949d0014/html5/thumbnails/15.jpg)
© University of South Carolina Board of Trustees
Student Example
Arrange the following aqueous solutions in order of
increasing boiling points:
0.03 molal urea(s) urea(aq) 0.03 m solute
0.01 molal NaOH Na+ + OH- 0.02 m ions
0.02 molal BaCl2 Ba2+ + 2 Cl- 0.06 m ions
0.01 molal Fe(NO3)3
![Page 16: © University of South Carolina Board of Trustees Adding a nonvolatile solute to a pure solvent causes: lower vapor pressure P = - P x sol higher.](https://reader031.fdocuments.in/reader031/viewer/2022032723/56649cff5503460f949d0014/html5/thumbnails/16.jpg)
© University of South Carolina Board of Trustees
Student Example
Arrange the following aqueous solutions in order of
increasing boiling points:
0.03 molal urea(s) urea(aq) 0.03 m solute
0.01 molal NaOH Na+ + OH- 0.02 m ions
0.02 molal BaCl2 Ba2+ + 2 Cl- 0.06 m ions
0.01 molal Fe(NO3)3 Fe3+ + 3 NO3- 0.04 m ions
![Page 17: © University of South Carolina Board of Trustees Adding a nonvolatile solute to a pure solvent causes: lower vapor pressure P = - P x sol higher.](https://reader031.fdocuments.in/reader031/viewer/2022032723/56649cff5503460f949d0014/html5/thumbnails/17.jpg)
© University of South Carolina Board of Trustees
Student Example
Arrange the following aqueous solutions in order of
increasing boiling points:
0.03 molal urea(s) urea(aq) 0.03 m solute
0.01 molal NaOH Na+ + OH- 0.02 m ions
0.02 molal BaCl2 Ba2+ + 2 Cl- 0.06 m ions
0.01 molal Fe(NO3)3 Fe3+ + 3 NO3- 0.04 m ions
![Page 18: © University of South Carolina Board of Trustees Adding a nonvolatile solute to a pure solvent causes: lower vapor pressure P = - P x sol higher.](https://reader031.fdocuments.in/reader031/viewer/2022032723/56649cff5503460f949d0014/html5/thumbnails/18.jpg)
© University of South Carolina Board of Trustees
Chapt. 12Solutions
Sec. 6Vapor Pressure of Liquid-Liquid
Solutions(skip)
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© University of South Carolina Board of Trustees
Chapt. 13Kinetics
(Later)
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© University of South Carolina Board of Trustees
Chapt. 14Chemical Equilibrium
Sec. 1What is Chemical Equilibrium?
![Page 21: © University of South Carolina Board of Trustees Adding a nonvolatile solute to a pure solvent causes: lower vapor pressure P = - P x sol higher.](https://reader031.fdocuments.in/reader031/viewer/2022032723/56649cff5503460f949d0014/html5/thumbnails/21.jpg)
© University of South Carolina Board of Trustees
What is Chemical Equilibrium?
● Both products and reactants remain
● Macroscopically Static: System has finished changing (not just slow)
![Page 22: © University of South Carolina Board of Trustees Adding a nonvolatile solute to a pure solvent causes: lower vapor pressure P = - P x sol higher.](https://reader031.fdocuments.in/reader031/viewer/2022032723/56649cff5503460f949d0014/html5/thumbnails/22.jpg)
© University of South Carolina Board of Trustees
Macroscopically Unchanging
2 NO2(g) N2O4(g)
brown colorless
equilibrium
Next Day
![Page 23: © University of South Carolina Board of Trustees Adding a nonvolatile solute to a pure solvent causes: lower vapor pressure P = - P x sol higher.](https://reader031.fdocuments.in/reader031/viewer/2022032723/56649cff5503460f949d0014/html5/thumbnails/23.jpg)
© University of South Carolina Board of Trustees
What is Chemical Equilibrium?
● Both products and reactants remain
● Macroscopically Static: System has finished changing (not just slow)
![Page 24: © University of South Carolina Board of Trustees Adding a nonvolatile solute to a pure solvent causes: lower vapor pressure P = - P x sol higher.](https://reader031.fdocuments.in/reader031/viewer/2022032723/56649cff5503460f949d0014/html5/thumbnails/24.jpg)
© University of South Carolina Board of Trustees
What is Chemical Equilibrium?
● Both products and reactants remain
● Macroscopically Static: System has finished changing (not just slow)
● Molecularly Dynamic: Forward and backward rates are in balance
![Page 25: © University of South Carolina Board of Trustees Adding a nonvolatile solute to a pure solvent causes: lower vapor pressure P = - P x sol higher.](https://reader031.fdocuments.in/reader031/viewer/2022032723/56649cff5503460f949d0014/html5/thumbnails/25.jpg)
© University of South Carolina Board of Trustees
Molecules Dynamic
2 NO2(g) N2O4(g)
brown colorless
equilibrium
Next Day
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© University of South Carolina Board of Trustees
What is Chemical Equilibrium?
● Both products and reactants remain
● Macroscopically Static: System has finished changing (not just slow)
● Molecularly Dynamic: Forward and backward rates are in balance
● Equilibrium concentrations independent of starting conditions
![Page 27: © University of South Carolina Board of Trustees Adding a nonvolatile solute to a pure solvent causes: lower vapor pressure P = - P x sol higher.](https://reader031.fdocuments.in/reader031/viewer/2022032723/56649cff5503460f949d0014/html5/thumbnails/27.jpg)
© University of South Carolina Board of Trustees
Independent of Starting Conditions
final: 2 NO2(g) N2O4(g) 2 NO2(g) N2O4(g)
initial: 100% NO2(g)100 % N2O4(g)
equilibriumconcentrations
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© University of South Carolina Board of Trustees
Chapt. 14Chemical Equilibrium
Sec. 1How are the Equilibrium
Concentrations Calculated?
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© University of South Carolina Board of Trustees
Experiments:Equilibrium concentrations from
several initial concentrations
Initial concentration, M
Equilibriumconcentration, M
[NO2] [N2O4]
0.0200 0.0000 0.0103 4.86 x 10-3
0.0000 0.0100 0.0103 4.86 x 10-3
2 NO2(g) N2O4(g)
junk
0.0300 0.0000 0.0134 8.29 x 10-3 0.62
0.0400 0.0000 0.0161 11.9 x 10-3 0.74
[N2O4][NO2]
Ratio I
0.47
0.47
[N2O4]
[NO2]
![Page 30: © University of South Carolina Board of Trustees Adding a nonvolatile solute to a pure solvent causes: lower vapor pressure P = - P x sol higher.](https://reader031.fdocuments.in/reader031/viewer/2022032723/56649cff5503460f949d0014/html5/thumbnails/30.jpg)
© University of South Carolina Board of Trustees
Experiments:Equilibrium concentrations from
several initial concentrations
Initial concentration, M
Equilibriumconcentration, M
Ratio I
[NO2] [N2O4]
0.0200 0.0000 0.0103 4.86 x 10-3 0.47 45.8
0.0000 0.0100 0.0103 4.86 x 10-3 0.47 45.8
0.0300 0.0000 0.0134 8.29 x 10-3 0.62 46.2
0.0400 0.0000 0.0161 11.9 x 10-3 0.74 45.9
2 NO2(g) N2O4(g)
Ratio II
[N2O4][NO2] [N2O4] [N2O4]
[NO2] [NO2]2
constant !
![Page 31: © University of South Carolina Board of Trustees Adding a nonvolatile solute to a pure solvent causes: lower vapor pressure P = - P x sol higher.](https://reader031.fdocuments.in/reader031/viewer/2022032723/56649cff5503460f949d0014/html5/thumbnails/31.jpg)
© University of South Carolina Board of Trustees
Fast Forward
>>>
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© University of South Carolina Board of Trustees
Equilibrium Constant Expression
2 NO2(g) N2O4(g)
2
45.9 2 4N O
NO
Example:
a A + b B c C + d D
c d
eq a bK
C D
A B
In General:
products – top
reactants – bottom
concentration
![Page 33: © University of South Carolina Board of Trustees Adding a nonvolatile solute to a pure solvent causes: lower vapor pressure P = - P x sol higher.](https://reader031.fdocuments.in/reader031/viewer/2022032723/56649cff5503460f949d0014/html5/thumbnails/33.jpg)
© University of South Carolina Board of Trustees
Equilibrium Constant Expression
2 NO2(g) 1 N2O4(g)
2
45.9 1
2 4
2
N O
NO
Example:
a A + b B c C + d D
eqK C D
A B
c d
a b
In General:
products – top
reactants – bottomEquilibrium Constant• a number• independent of starting amounts
![Page 34: © University of South Carolina Board of Trustees Adding a nonvolatile solute to a pure solvent causes: lower vapor pressure P = - P x sol higher.](https://reader031.fdocuments.in/reader031/viewer/2022032723/56649cff5503460f949d0014/html5/thumbnails/34.jpg)
© University of South Carolina Board of Trustees
Examples
32
23
eqK O
O
2 2
2eqK
H CO
CO H O
2
2eqK
Cl
Cl
CO(g) + H2O(g) H2(g) + CO2(g)
Cl2(g) 2 Cl•(g)
2 O3(g) 3 O2(g)