Page 319 - 9780077418427.pdf

/Users/user-f465/Desktop
tiL12214_ch11_275-298.indd Page 296 9/3/10 6:12 PM user-f465
tiL12214_ch11_275-298.indd Page 296 9/3/10 6:12 PM user-f465 /Users/user-f465/Desktop

35. The ice that forms in freezing seawater is 46. The substance that is a nonelectrolyte is
a. pure water. a. sodium chloride, NaCl.
b. the same salinity as liquid seawater. b. copper sulfate, CuSO 4 .
c. more salty than liquid seawater. c. glucose, C 6 H 12 O 6 .
d. denser than liquid seawater. d. aluminum chloride, AlCl 3 .
36. Salt solutions freeze at a lower temperature than pure water because 47. Salt is spread on icy roads because it
a. more ionic bonds are present. a. lowers the freezing point of water.
b. salt solutions have a higher vapor pressure. b. increases the freezing point of water.
c. ions get in the way of water molecules trying to form ice. c. increases the boiling point of water.
d. salt naturally has a lower freezing point than water. d. increases the melting point of water.
37. Which of the following would have a pH of less than 7? 48. Hard water is a solution of
+ –
a. A solution of ammonia a. Na and Cl ions.
+ +
b. A solution of sodium chloride b. Na and K ions.
2+ 2+
c. Pure water c. Ca and Mg ions.
2+ –
d. Carbonic acid d. Ba and Cl ions.
38. Which of the following would have a pH of more than 7? 49. A solution has a pH of 9. This means that the solution is
a. A solution of ammonia a. acidic.
b. A solution of sodium chloride b. neutral.
c. Pure water c. basic.
d. Carbonic acid d. unknown.
39. Solutions of acids, bases, and salts have what in common? All have Answers
a. proton acceptors.
1. c 2. a 3. a 4. a 5. a 6. c 7. b 8. a 9. d 10. b 11. b 12. d 13. a 14. b
b. proton donors.
15. b 16. b 17. b 18. b 19. c 20. a 21. c 22. b 23. b 24. d 25. a 26. c
c. ions.
27. d 28. a 29. c 30. b 31. b 32. c 33. b 34. b 35. a 36. c 37. d 38. a
d. polar molecules.
39. c 40. d 41. a 42. b 43. c 44. c 45. b 46. c 47. a 48. c 49. c
40. When a solution of an acid and a base are mixed together,
a. a salt and water are formed.
b. they lose their acid and base properties. QUESTIONS FOR THOUGHT
c. both are neutralized.
d. All of the above are correct. 1. How is a solution different from other mixtures?
41. A substance that ionizes completely into hydronium ions is 2. Explain why some ionic compounds are soluble while others are
known as a insoluble in water.
a. strong acid. 3. Explain why adding salt to water increases the boiling point.
b. weak acid.
4. A deep lake in Minnesota is covered with ice. What is the
c. strong base.
water temperature at the bottom of the lake? Explain your
d. weak base.
reasoning.
42. A scale of values that expresses the hydronium ion concentration
5. Explain why water has a greater density at 4°C than at 0°C.
of a solution is known as
6. What is hard water? How is it softened?
a. an acid-base indicator.
b. the pH scale. 7. According to the definition of an acid and the definition of a
c. the solubility scale. base, will the pH increase, decrease, or remain the same when
d. the electrolyte scale. NaCl is added to pure water? Explain.
43. Substance A has a pH of 2 and substance B has a pH of 3. This 8. What is a hydrogen bond? Explain how a hydrogen bond
means that forms.
a. substance A has more-basic properties than substance B. 9. What feature of a soap molecule gives it cleaning ability?
b. substance B has more-acidic properties than substance A. 10. What ion is responsible for (a) acidic properties and (b) basic
c. substance A is 10 times more acidic than substance B. properties?
d. substance B is 10 times more acidic than substance A.
11. Explain why a pH of 7 indicates a neutral solution—why not
44. Water is a (an) some other number?
a. ionic compound.
b. covalent compound.
c. polar covalent compound. FOR FURTHER ANALYSIS
d. triatomic molecule.
45. The heat of fusion, specific heat, and heat of vaporization of 1. What are the basic differences and similarities between the
water are high compared to similar substances such as hydrogen concentration measures of salinity and percent by weight?
sulfide, H 2 S, because 2. Compare and contrast the situations where you would express
a. ionic bonds form in water molecules. concentration in (1) parts per million, (2) parts per billion,
b. hydrogen bonds form between water molecules. (3) percent (volume or weight), and (4) salinity.
c. covalent bonds form between water molecules.
d. covalent bonds form in water molecules.

296 CHAPTER 11 Water and Solutions 11-22