Dr. Herrick's CH222
Pressure Quiz 6

     

 

      

Solutions
Copyright D. Herrick

 

20 Questions from past exams.
Practice for speed.  Aim for 2 minutes per problem.

 
 
 
Constants:
Gas constant: R = 0.08206 L-atm/mol-K = 8.314 J/mol-K

properties of water
   density = 1.0 g/mL
   Kb = 0.52C/m

   Kf = 1.86C/m
   freezing point = 0.00C

   boiling point = 100.00C
 

 

1. What is the strongest type of intermolecular force between solute and solvent in an aqueous solution of KCl?
A) hydrogen bonding
B) dipole-dipole
C) ion-dipole  
D) ion-induced dipole
E) dipole-induced dipole
F) dispersion
 
2. What is the strongest type of intermolecular force between solute and solvent in a  solution of Br2 in CCl4
A) hydrogen bonding
B) dipole-dipole
C) ion-dipole
D) ion-induced dipole
E) dipole-induced dipole
F) dispersion  

   

3. What is the strongest type of intermolecular force between solute and solvent in a solution of CH3NH2 in hexane (C6H14)?
A) hydrogen bonding
B) dipole-dipole
C) ion-dipole
D) ion-induced dipole
E) dipole-induced dipole  
F) dispersion

       

4. What is the strongest type of intermolecular force between solute and solvent in a solution of CH3NH2 in NH3?
A) hydrogen bonding  
B) dipole-dipole
C) ion-dipole
D) ion-induced dipole
E) dipole-induced dipole
F) dispersion

 

5. Diethyl ether has a vapor pressure of 400.0 torr at 18C .  When a sample of a nonvolatile molecular solid is dissolved in ether, the vapor pressure of the solution is 192 torr.  What is the mole fraction of the solute in the solution? 
A)  0.73 B)  0.48 C)  0.50 D)  0.52   E)  0.36

     

6. Which aqueous solution has the highest number of moles of solute particles in 1.00 L of solution?
A) 0.19 M CaCl2  
B) 0.14 M FeCl3
C) 0.27 M KCl
D) 0.55 M ethanol (CH3CH2OH)

     

7. The freezing point of benzene is 5.5C.  What is the freezing point of a solution of 2.46 g of naphthalene (C10H8, MW = 128.2) in 512 g of benzene (Kf of benzene = 4.90C/m)?
A)  5.7C B)  5.3C   C)  5.9C D)  5.1C  E)  4.9

      

8. Which aqueous solution has the lowest boiling point?
A)  0.19 m CaCl2 
B) 0.14 m FeCl3
C) 0.27 m KCl  
D) 0.55 m ethanol (CH3CH2OH)

    

9. Human blood has a molar concentration of solute particles of 0.30 M.  What is the osmotic pressure (in atm) of blood at 37C?
A)  8.0 B)  7.3 C)  6.9 D)  7.0 E)  7.6   

        

10. Gases like oxygen that are weakly soluble in water tend to be more soluble under conditions of
A) low pressure and low temperature
B) low pressure and high temperature
C) high pressure and low temperature  
D) high pressure and high temperature
E) solubility is independent of pressure and temperature

     

11. Calculate the vapor pressure (torr) of a solution of benzene and toluene in which the mole fraction of toluene is 0.35.  The vapor pressure of pure benzene at the temperature of the solution is 75 torr; the vapor pressure of pure toluene is 22 torr. 
A)  39 B)  56   C)  81 D)  27 E)  45

 

12. A solution is 15% glucose (MW = 180) and 85% water (MW = 18) by mass.  The density of the solution is 1.2 g/mL.  The molality of glucose in the solution is
A)  0.29 B)  0.84 C)  0.15 D)  1.20 E)  0.98  

     

13. An aqueous solution containing an unknown nonelectrolye solute freezes at -5.37C; the molality of the solute in this solution is
A)  10.33 B)  5.16 C)  1.05 D)  2.89   E)  3.65

     

14. Potassium salts are strongly ionized when they dissolve in water.  Calculate the boiling point of a solution that contains 2.0 mol of K3PO4 dissolved in 500 g of water.
A) 108.3C  
B) 103.5C  
C) 105.7C 
D) -94.0C
E) 106.4C

        

15. An "antifreeze" aqueous solution of ethylene glycol has a freezing point of -10.0C; estimate the boiling point of the same solution. 
A) 97.4C  D) 103.5C 
B) 100.1C  E) 108.3C 
C) 106.4C  F) 102.8C   

     

16. If C is the molar concentration of a protein in a water solution, the expression for the osmotic pressure of the solution is 
A) RT/C D) RTC  
B) CT/R E) T/RC
C) RC/T F) C/RT

      

17. When 1.0 g of glucose (MW = 180) is dissolved in water the osmotic pressure of the solution is 100 torr.  When 3.0 g of an unknown protein is dissolved in the same amount of water the osmotic pressure is 4.2 torr.  Estimate the molecular weight of the protein.
A) 12,900  D) 14,200
B) 10,300 E) 28,400
C)  6,800 F) 19,600

    

18. Which of the following is NOT a colligative property?
A) freezing point lowering
B) osmotic pressure
C) expansion on freezing  
D) boiling point elevation
E) vapor pressure lowering

      

19. Predict the alcohol with the lowest solubility in water:
A) CH3OH
B) CH3CH2OH
C) CH3CH2CH2OH
D) CH3CH2CH2CH2CH2CH2OH  
E) HOCH2CH2OH

     

20. Which soluble ionic salt is expected to have the largest (most negative) heat of hydration?
A) KCl
B) LiF 
C) NaBr
D) CsI
E) RbCl

 


 

 

   Copyright D. Herrick