Unit Five Worksheet WS DC U5 Name Period Chapter Thirteen Drawing. Draw electron dot structures for the following molecules or polyatomic ions. 1. HBr (hydrobromic acid) 5. PF 3 (phosphorus trifluoride) 2. C 2 H 2 (ethyne, or acetylene) 6. NH 4 + (ammonium ion) 3. ClO 4 (chlorate ion) 7. SO 3 (sulfite ion) 4. HCN (hydrogen cyanide) 8. Br 2 (diatomic bromine) page 1 WS DC U5
Short Answer. Answer the following questions. 9. How many resonance structures can be drawn for the carbonate ion? Show the structural formulas for each. 10. How many resonance structures can be drawn for the nitrite ion? Show the electron dot structures for each. Drawing. Draw the electron dot structure for each molecule or polyatomic ion. Then identify the molecular geometry of the following molecule or polyatomic ion. 11. NO 3 - (nitrate ion) 13. CCl 4 (carbon tetrachloride) 12. MnO - 4 (permanganate ion) 14. 3- PO 4 (HINT: Assume Mn has 7 valance e.) (phosphate ion) page 2 WS DC U5
15. PI 5 (phosphorus pentaiodide) 17. PO 3 3- (phosphite ion) 16. NH 3 (ammonia) 18. CO 2 (carbon dioxide) Short Answer. Answer the following questions. What type of bond nonpolar covalent, polar covalent, or ionic will form between each of the following pairs of atoms? 19. Na and O: 20. Li and Cl: 21. P and O: 22. N and N: 23. Al and Cl: 24. O and F: page 3 WS DC U5
25. Explain why most chemical bonds would be classified as either polar covalent or ionic. (HINT: Consider why most are NOT nonpolar covalent.) 26. Would you expect carbon monoxide to be a polar or nonpolar molecule, and is there any difference in polarity between carbon monoxide and carbon dioxide? Explain. Draw the structural formulas for each molecule and identify polar covalent bonds by assigning the slightly positive (δ+) and the slightly negative (δ ) charges to each atom in each bond. Then identify the overall molecule as polar or nonpolar. 27. NH 3 29. CF 4 28. CCl 4 30. HF 31. Which compound would you expect to have the higher melting point: OCl 2 or CaCl 2? Explain. page 4 WS DC U5
Table Completion. Complete the following table. Number of valence Symbol electrons in atom/ion Electron dot formula 32. 33. 34. Electron configuration S 2 8 35. 36. Ca 2+ 37. 1s 2 2s 2 2p 6 3s 2 3p 6 Na 38. 39. Rb + 40. 41. 42. 43. 44. 45. Short Answer. Answer the following questions. How many electrons will each of the following elements gain or lose in forming an ion? State whether each is a cation or anion. Strontium: Number of e lost or gained: 46. Anion/Cation? 49. Phosphorus: Number of e lost or gained: 47. Anion/Cation? 50. Bromine: Number of e lost or gained: 48. Anion/Cation? 51. 52. What is the relationship between the group number of the representative elements and the number of valence electrons? page 5 WS DC U5
53. Why do metals tend to form cations while nonmetals tend to form anions? Chapter Fourteen Short Answer. Answer the following questions. 54. In your own words, explain what a hydrogen bond is. 55. Depict the hydrogen bonding between three water molecules in a drawing. 56. How is hydrogen bonding responsible for the high boiling point of water? 57. Explain how large bodies of water are able to moderate air temperature. Short Answer. Answer the following questions. 58. Explain why it gets warmer before it rains. 59. Explain why the density of ice at 0 C is less than the density of liquid water at 0 C. page 6 WS DC U5
60. Explain why water has a relatively high boiling point and heat of vaporization. 61. What is the difference between the structure of liquid water and the structure of ice? How does this explain why ice floats in water? 62. Explain why water has a high surface tension. Chapter Fifteen Identify the solute and solvent in a dilute aqueous solution of sodium hydroxide. 63. Solute: 64. Solvent: 65. Give an example of a polar molecular compound that dissolves in water and that is a nonelectrolyte. Which of the following compounds are soluble in water? Which are insoluble? 66. CaCl 2 : 67. N 2 : 68. HBr: 69. NH 4 C 2 H 3 O 2 : page 7 WS DC U5
Write equations to show how the following compounds dissociate in water. 70. NH 4 NO 3 (s) 71. K 2 SO 4 (s) Write the formulas for the following hydrates. 72. Calcium sulfate decahydrate: 73. Cobalt (II) chloride hexahydrate: 74. Find the percent by mass of water in NiCl 2 6H 2 O. ] 75. Why is using water to clean a paintbrush covered with oil-based enamel not an effective cleanup method? 76. How can a supersaturated solution be prepared? 77. You are given a clear aqueous solution containing potassium nitrate (KNO 3 ). How would you determine experimentally if the solution is unsaturated, saturated, or supersaturated? Short Answer. Write complete balanced net ionic equations based on the following chemicals reacting. 78. Lead (II) nitrate and sulfuric acid page 8 WS DC U5
79. Sodium phosphate and iron (III) chloride 80. Ammonium sulfuide and cobalt (II) nitrate 81. Sulfuric acid and barium chloride 82. Aluminum sulfate and ammonium hydroxide 83. Silver nitrate and dihydrogen sulfide 84. Calcium chloride and lead (II) nitrate 85. Calcium nitrate and sodium carbonate 86. Hydrochloric acid and barium hydroxide 87. Iron (III) nitrate and sodium hydroxide 88. What are colligative properties of solutions? Give examples of three types of colligative properties. page 9 WS DC U5
89. How many particles in solution are produced by each formula unit of potassium carbonate, K 2 CO 3? 90. How many moles of particles would 3 mol Na 2 SO 4 give in solution? 91. What kind of property is vapor-pressure lowering? An equal number of moles of NaCl and CaCl 2 are dissolved in equal volumes of water. Which solution has the lower 92. freezing point? 93. vapor pressure? 94. boiling point? 95. Why does a solution have an elevated boiling point and a depressed freezing point compared with the pure solvent? page 10 WS DC U5