Northrup's Chem 112 Section TTU General Chemistry

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Chem 112 - Quiz 1C - Spring, 1998
Chapter 14: Solutions

1. Another name for a true solution is:

a) heterogeneous mixture
b) homogeneous mixture
c) suspension
d) colloid

2. Which factor below would generally favor solution formation?

a) nonpolar solvents
b) endothermic heat of solution
c) large crystal lattice energy of solute
d) entropy of mixing

3. Which substance would have the highest solubility in hexane, C6H14?

a) NaCl
b) H2O
c) S8
d) NH3

4. A 10.0% aqueous solution of glucose C6H12O6 by mass used in intravenous feeding would have what molality?

a) 0.617 mol/kg
b) 0.555 mol/kg
c) 0.100 mol/kg
d) 0.111 mol/kg

5. What additional piece of information would be required to calculate the molarity of the solution in Problem #4?

a) mole fraction of the solute
b) molecular weight of solvent
c) mass density of the solution
d) heat capacity of the solution

6. A colloidal suspension in which tiny droplets of oil are suspended in soapy water (when doing dishes, etc.) is called:

a) a gel
b) an aerosol
c) a foam
d) an emulsion

7. Oil is solubilized in soapy water by the:

a) formation of micelles
b) Tyndall effect
c) reverse osmosis process
d) eutrophication process

8. Suppose 3.6 grams of an unknown solute is dissolved in 100 grams of liquid benzene and the freezing point of the liquid is lowered by 2.56° C. Which of the following substances is this unknown substance most likely to be? The cryoscopic constant of benzene is 5.12° C/molal.

a) C6H14
b) C5H12
c) H2O
d) NaCl

9. Identify the INCORRECT statement below:

a) Henry's Law relates the pressure of a gas above a liquid to the concentration of dissolved gas.
b) The solubility of a substance generally increases when the temperature of solution is increased.
c) A colligative property is a physical property of a solution that depends on the number of solute particles, and not their identity.
d) An endothermic heat of solution for NaCl(aq) implies that its solubility would increase as T increases.
e) Raoult's Law relates the vapor pressure of a liquid to its mole fraction in the solution phase.

10. Colloids can be distinguished from true solutions by:

a) the hydrophobic nature of the solute
b) the dispersing medium
c) the fact that no settling out occurs in the colloidal dispersion
d) the sizes of the dispersed particles

KEY

1)b 2)d 3)c 4)a 5)c 6)d 7)a 8)b 9)b 10)d
To send electronic mail to Dr. Northrup ====> snorthrup@tntech.edu, or call 615-372-3421, or come to Foster Hall 219