Answers to 1st Semester Sample Exam Questions

1. d        2. b    3. a    4. a    5. a    6. c    7. b    8. b    9. c    10. b    11. d    12. c    13. c    14. b    15. b    16. d

17. c    18. c    19. b    20. b    21. c    22. d    23. a    24. b    25. b    26. e    27. b    28. b    29. b    30. c    31. a

32. d    33. e    34. a    35. x    36. e    37. b    38. c    39. d    40. d    41. b    42. c    43. c    44. d    45. b    46. b

47. a    48. e    49. c    50. b    51. b    52. b    53. a    54. b    55. a    56. e    57. a    58. c    59.a    60. a    61. a

62. a    63. a    64. d    65. c    66. d    67. c    68. e    69. ab    70. de    71. b    72. abc    73. be    74. abd

75. ce    76. bd    77. c    78. bcd    79. ade    80. bc    81. acd    82. ad

Part II:

1.  Cu₂S

2.  (a) 4Hg + O₂ --> 2Hg₂O
     (b) 2C₄H₁₀ + 13 O₂ --> 8 CO₂ + 10 H₂O
     (c) 2 Al + 3 CuCl₂ --> 2 AlCl₃ + 3 Cu
     (d) 2 Fe₂O₃  --> 4 Fe + 3 O₂

3. C₅H₁₂ + 8 O₂ --> 5 CO₂ + 6 H₂O;  V_CO2 = 388.9 L

4. (a) 416 g        (b) AgNO₃        (c) 1.07 mol or 68.2 g Cu

5. 58.0 g        6. 1940 kJ        7. 4 NH₃ + 3 O₂ --> 4 NO + 2 H₂O;  DH = 63 kJ

8.  Atomic Radius decreases up a group and from left to right across a period, whereas Ionization Energy increases up a group and from left to right across a period.  As the AR gets smaller it becomes increasingly more difficult to remove an electron from the smaller atoms.  The smaller AR indicates that the valence electrons are being held more tightly.  If they are held more tightly more IE will be required to remove these tightly held electrons.

9. V₂ = 847 mL        10. m = 1.21 g

11. Solid: fixed volume and fixed shape, non-compressible, vibrational motion only, rigid structure with highly order arrangement of particles, intermolecular forces are very significant.

        Liquid: fixed volume, but variable shape, non-compressible, all types of motion present, atoms touching one another but not in fixed locations, they move past one another, intermolecular forces are significant holding the particles in contact, some organization, liquids flow

        Gas: variable volume and shape, particles very spread apart, low density, all types of motion present, particles collide perfectly elastically, no significance to intermolecular forces, no organization, gases flow

12. Ideal gases make two key assumptions that are not true for real gases.  These are that there are no intermolecular forces between gaseous particles and that the gas particles themselves have no volume.  These assumptions are good when the temperature of a gas is high and the pressure on it is low.

13.  Rutherford performed the gold foil experiment in which he fired alpha particles, atomic bullets, at a thin piece of gold foil.  To his surprise most of the particles passed through unaffected by the foil, and even more surprisingly some were deflected significantly and even bounced back.  From this he concluded that the atom contains a tiny, dense, positively charged nucleus which contains most of the mass.  The electrons with their negative charge and insignificant mass are outside the nucleus in the electron cloud.  Two questions remained for Bohr and others to answer.  1. Why would a positively charged nucleus which contains protons stick together.  2. Why don't the electrons fall into the nucleus.

Extra Credit:  You figure this one out!