Chem II Chapter 13

12 Questions
chem II chapter 13

This quiz is to review for the Chapter 13 test.

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Questions and Answers
  • 1. 
    What increases when 2 pure substances are mixed to form a solution?
    • A. 

      Heat

    • B. 

      Entropy

    • C. 

      Solubilty

    • D. 

      Nothing increases

  • 2. 
    What is the molality of a solution of 50 g of CH3CH2CH2OH in 152 mL water, if the density of water is 1 g/mL?
    • A. 

      5.47 m

    • B. 

      0.00547 m

    • C. 

      0.833m

    • D. 

      0.183m

  • 3. 
    A 2.300 molal solution of KCl is prepared. How many grams of KCl are present in a sample containing 5.0 kg of water?
    • A. 

      546.7 g

    • B. 

      856.8 g

    • C. 

      113.7g

    • D. 

      74.5g

  • 4. 
    The solubility of oxygen gas in water is 0.590 g/L at a pressure of 15 atm. What is the Henry's law constant for oxygen gas in units of L-atm/mol?
    • A. 

      0.00393

    • B. 

      0.00123

    • C. 

      814

    • D. 

      1.26

  • 5. 
    At a given temperature, you have a mixture of benzene (vapor pressure of pure benzene = 745 torr) and toluene(vapor pressure of pure toluene = 290 torr). The mole fraction of benzene in solution is 0.59. Assuming ideal behavior, calculate the mole fraction of toluene in the vapor above the solution.
    • A. 

      0.123

    • B. 

      0.778

    • C. 

      0.641

    • D. 

      0.359

  • 6. 
    150g of NaCl dissolves in 1 kg of water at 25oC. the vapor pressure of pure water at this temperature is 23.8 torr. Determine the vapore pressure of the solution.
    • A. 

      21.8 torr

    • B. 

      22.5 torr

    • C. 

      20.6 torr

    • D. 

      19.7 torr

  • 7. 
    • A. 

      92 g/mol

    • B. 

      215 g/mol

    • C. 

      118 g/mol

    • D. 

      314 g/mol

  • 8. 
    Colligative properties depend on ..
    • A. 

      The chemical properties of the solute

    • B. 

      The chemical properties of the solvent

    • C. 

      The masses of the individual ions

    • D. 

      The number of particles dissolved

  • 9. 
    Raoult's law relates the vapor pressure of the solvent above the soltion to its mole fraction in the solutio. Which of the following is an accurate statement?
    • A. 

      Raoult's law applies exactly to all solutions

    • B. 

      Raoult's law works best when applied to concentrated solutions

    • C. 

      Roaults law works best when applied to dilute solutions

    • D. 

      Raoult's law applies only to non-ideal solutions

  • 10. 
    The Tyndall effect..
    • A. 

      Is observed in concentrated solutions

    • B. 

      Is obsreved only in dilute solultions

    • C. 

      Is observed in colloidal dispersions

    • D. 

      Is caused by Brownian motion

  • 11. 
    When a 20 g sample of an unknown compound is dissolved in 500g of benzene, the freeezing point of the resulting solution is 3.77oC. The freezing point of pure benzene is 5.48oC and the K value for benzene is 5.12. Calcualte the molar mass of the unknown
    • A. 

      160 g/mol

    • B. 

      80 g/mol

    • C. 

      120 g/mol

    • D. 

      140 g/mol

  • 12. 
    Calculate the molarity of a solution contians KCl and water whose osmotic pressure at 21oC is 100 torr.
    • A. 

      0.005 M

    • B. 

      0.01 M

    • C. 

      0.08 M

    • D. 

      0.0025 M