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Chapter 17 Test

EM NO ETIRW ESAELP

For the following molecular structures predict whether the molecule is polar or non-polar.
Note: to receive full credit you must show how you made your prediction (i.e. show arrows)

1. (3 pts) CO2 4. (3 pts) H2O
2. (3 pts) CH2Cl2 5. (3 pts) PH3
3. (3 pts) CBr4 6. (3 pts) NH4Cl

Identify whether the intermolecular attractions between the following molecules will be hydrogen
bonding, dipole interactions, or dispersion forces:

7. (2 pts) HCl

8. (2 pts) HF

9. (2 pts) CH3Br

10. (2 pts) CH4

Predict whether each of the following substances is soluble in water. Give reasons for your
predictions:

11. (2 pts) HF

12. (2 pts) NaNO3

13. (2 pts) CCl4

14. (4 pts) Which of the following two molecules is more polar? Explain.

HCl HI

15. (4 pts) Would NaCl dissolve in CCl4? Explain.

16. (4 pts) A student adds a few salt crystals to a salt water solution. The salt crystals
dissolve immediately. Was the original solution saturated or unsaturated? Explain.

17. (4 pts) Explain in terms of gas solubility whether a warm soda or a cold soda will go flat
more quickly.

18. (4 pts) Explain in terms of Henry's law why keeping a cap on a bottle of soda will prevent
it from going flat.

Calculate the molarity of the following solutions:

19. (4 pts) 2.5 mol CH3COONa in 5.0 L of solution

20. (5 pts) 46.0 g of NaF in 5,500.0 mL of solution

21. (4 pts) How many grams of K2SO4 are in 55.0 mL of a 0.40 M K2SO4 solution?

22. (4 pts) Which of the following solutions would conduct an electric current? Explain.

MgCl2 CCl4

23. A. (4 pts) How many mL of a 12.0 M H2SO4 solution are required to make 200.0 mL
of a 0.40 M H2SO4 solution?

B. (3 pts) Describe how you would make this solution.

24. (4 pts) Is it possible to make a 13.0 M HCl solution by diluting a 12.0 M HCl solution?
Explain.

25. (3 pts) 5.0 moles of NaI are dissolved in 50.0 mL of solution. Calculate the molarity of
this solution.

26. (3 pts) If 45 mL of H2O are added to the solution in problem 25, calculate the molarity of
the resulting solution.

Calculate the concentration in ppm for the following:

27. (5 pts) 22.0 mg of Cd in 23.4 kg of solution

28. (4 pts) The concentration of Pb in spring water is 2.3 ppm. How many grams of Pb could
be found in a 2.0 L bottle of spring water?

Which of the following solutions would have a lower freezing point? Show work.

29. (3 pts) 1.0 M K3PO4 1.0 M K2SO4

30. (3 pts) 2.0 M HF 1.5 M H2SO4

31. (5 pts) Describe in detail why H2O is a liquid at room temperature and why methane
(CH4) is a gas at room temperature. Include in your explanation a discussion about
intermolecular attractions.

32. (3 pts) Describe three characteristics that you would like your ideal girlfriend/boyfriend to
possess (please use no X-rated terms).

 


Answers

  1. non polar
  2. polar
  3. non polar
  4. polar
  5. polar
  6. ionic, polar
  7. dipole
  8. hydrogen bonding
  9. dipole
  10. dispersion
  11. soluble
  12. soluble
  13. insoluble
  14. Cl is more electronegative, therefore HCl is more polar
  15. NaCl is ionic (polar), CCl4 is non polar, therefore it won't dissolve according to the rule of "like dissolves like"
  16. unsaturated b/c it was able to dissolve more solute
  17. The solubility of a gas goes down as temp. goes up, therefore warm soda holds less gas, therefore it will go "flat" faster
  18. Solubility of a gas goes up with increasing pressure. Keeping the cap on a bottle maintains high pressure, therefore the soda stays fizzy
  19. .50 M
  20. .199 M
  21. 3.8 g
  22. MgCl2 is ionic and breaks into ions in solution, CCl4 does not and won't conduct (ions required to conduct)
  23. 6.7 mL
  24. No
  25. 1.0 x 102
  26. 53 M
  27. .940 ppm
  28. .0046 g
  29. K3PO4
  30. H2SO4
  31. H2O is "stickier" due to hydrogen bonding, therefore it takes more energy to separate it into a gas, therefore it has a higher boiling point.