AP Chemistry 1st Semester Final Review Name:

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1 AP Chemistry 1st Semester Final Review Name: Which of the following contains only sigma (s) bonds? 5. H2O(g) + CO(g) H2(g) + CO2(g) A) CO2 B) C3H6 C) CH3Cl D) N2O3 E) SiO2 2. What is the equilibrium law expression for the above reaction? A) B) C) D) 3. H2O(g) + CO(g) H2(g) + CO2(g) A closed container is initially filled with H2O and CO. As the reaction proceeds towards equilibrium the A) [CO] and [CO2] both increase B) [CO] and [CO2] both decrease C) [CO] increases and [CO2] decreases D) [CO] decreases and [CO2] increases E) [CO] decreases and [CO2] remains constant 4. Which of the following is characteristic of all systems at equilibrium? A) Activation energy is not required. B) The addition of a catalyst does not change equilibrium concentrations. C) Changes do not occur at the microscopic level. D) Two opposing reactions occur at the same rate. E) Temperature and pressure affect the equilibrium position equally. Initially 5.0 moles of H2O and 4.0 moles of CO were reacted in the system above. At equilibrium, it is found that 2.0 moles of H2 are present. How many moles of H2 O remain in the mixture? A) 1.0 moles B) 2.0 moles C) 3.0 moles D) 4.0 moles E) 5.0 moles 6. Base your answer to the following question on the equation and the choices provided. CN (aq) + H2O(l) «HCN(aq) + OH (aq) (A) increases (B) decreases (C) remains the same (D) increases, then decreases (E) decreases, then increases If the pressure is increased, the [OH ] 7. When at equilibrium, which reaction shifts to the right if pressure is increased? A) 2 NO(g) «N2(g) + O2(g) B) 2 H2(g) + O2(g) «2 H2O(g) C) 2 NH3(g) «N2(g) + 3 H2(g) D) 2 CO2(g) «2 CO(g) + O2(g) E) 2 SO3(g) «2 SO2(g) + O2(g) Page 1

2 8. N2(g) + 3 H2(g) 2 NH3(g) + 22 kcal Which shows what happens to the concentrations of the three gases when some NH3 is removed from the above equilibrium system with temperature and pressure remaining constant. A) B) C) D) HBr(g) + O2(g) 2 H2O(g) + 2 Br2(g) H = 276kJ Which change to the above system at equilibrium will increase the concentration of Br2(g)? A) An increase in pressure B) An increase in temperature C) The removal of oxygen, O2 D) The addition of water vapor, H2O(g) E) The removal of HBr(g) 12. N2(g) + 3 H2(g) 2 NH3(g) + 24 kcal Which change will increase the above equilibrium concentration of ammonia, NH3? A) A decrease in the total pressure B) A decrease in the concentration of H2(g) C) An increase in the volume of the reaction chamber D) A decrease in the temperature of the reaction chamber E) A decrease in the concentration of N2(g) 13. At equilibrium, represented by the equation below, the [NO] is 2.0 M; [O2] is 3.0 M; [N2O5] is 8.0M. 4 NO(g) + 3 O2(g) 2 N2O5(g) + Heat 9. AgCl(s) + 2 S2O3 2 (aq) Ag(S2O3)2 3 (aq) + Cl (aq) If more S2O3 2 is added to the above system at equilibrium, the A) amount of AgCl(s) increases B) rate of forward reaction decreases C) concentration of Cl (aq) increases D) concentration of Ag(S2O3)2 3 (aq) decreases E) equilibrium cannot be reestablished 10. PbI2(s) + heat Pb 2+ (aq) + 2I (aq) What is the numerical value of the equilibrium constant, K, at this temperature? A) 0.15 B) 0.94 C) 1.5 D) 1.6 E) I2(g) 2 I(g) K = 9.0 moles/liter At equilibrium, the concentration of I2 is 1.0 mole/liter. What is the concentration of the I at this temperature if the system behaves according to the above equation? A) 9.0 moles/liter B) 2.0 moles/liter C) 3.0 moles/liter D) 4.5 moles/liter E) 6.0 moles/liter Which of the following changes would result in more PbI2 dissolving? A) Adding more PbI2 B) Increasing the pressure C) Decreasing the temperature D) Increasing the temperature E) Adding some Pb(NO3)2 Page 2

3 15. The relative number of molecules with a given kinetic energy is plotted against kinetic energy. An uncatalyzed reaction with an activation energy, Ea, is being considered. In which region of the above kinetic energy distribution graph will all collisions result in a chemical reaction? A) area I only B) area IV only C) areas II and III only D) areas I, II and III only E) areas I and IV only Base your answers to questions 16 through 21 on the diagram shown below. 16. A catalyst would change A) 1 and 6 B) 2 and 3 C) 3 and 4 D) 4, 5 and 6 E) 3 and Which represents the heat of reaction? A) 1 B) 2 C) 3 D) 4 E) Which represents the activation energy for the forward reaction? A) 1 B) 2 C) 3 D) 4 E) Which represents the energy of the activated complex? A) 6 B) 2 C) 3 D) 4 E) The products have an energy represented by number A) 6 B) 2 C) 3 D) 4 E) The least stable species in this diagram is the A) reactants B) products C) activated complex D) endothermic reaction 22. Potassium sulfide is completely ionized in water: K2S(s) 2 K + (aq) + S 2 (aq) Which of the following equations is true? A) [K + ] = [S 2 ] = 2 [K2S] B) [K + ] 2 = [S 2 ] C) [K + ] = [S 2 ] 2 D) [K + ] = 2 [S 2 ] E) 2 [K + ] = [S 2 ] 23. When 250. ml of 0.36 M Sr(OH)2 are added to 750. ml of water, the resulting ion concentrations are A) [Sr 2+ ] = 0.12 M and [OH ] = 0.12 M B) [Sr 2+ ] = 0.12 M and [OH ] = 0.24 M C) [Sr 2+ ] = M and [OH ] = M D) [Sr 2+ ] = M and [OH ] = M E) [Sr 2+ ] = M and [OH ] = 0.24 M 24. Which of the following involves the breaking of covalent bonds? A) C(graphite) C(g) B) H2O(s) H2O(l) C) Ne(g) Ne(s) D) Co(l) Co(s) E) Ti(l) Ti(s) Page 3

4 Base your answers to questions 28 through 30 on the following bonding types. 25. According to the above table, which substances have metallic bonding? A) I and IV B) I and V C) III and IV D) II and V E) II and IV 26. The element X forms diatomic molecules with each of the elements P, Q, S, T. Based on the table above, which lists the compounds in the order of increasing ionic character? Lowest Highest A) X P X Q X S X T B) X Q X P X T X S C) X Q X T X P X S D) X S X T X P X Q E) X Q X P X S X T 27. A certain solid is insoluble in water, does not conduct electricity in either the solid or liquid state and melts at a temperature above 1500 C. Which type of bonding is most likely between lattice points in its crystalline structure? A) Ionic B) Metallic C) Network covalent D) Molecular covalent E) Coordinate covalent (A) Coordinate covalent bonding (B) Network covalent bonding (C) Ionic bonding (D) Metallic bonding (E) Hydrogen bonding 28. Bonding associated with nitrogen, oxygen and fluorine only 29. Substances with this bonding type exhibit good electrical and thermal conductivity 30. Type of bonding exhibited by two atoms with a large electronegativity difference 31. Which of the following has the lowest boiling point? A) SiO2 B) LiCl C) NH3 D) C2H6 E) Fe Base your answers to questions 32 through 35 on the following substances (all solids). (A) RbCl (B) SiO2 (C) Ag (D) CN (E) C3H8 32. Contains strong multiple covalent bonds 33. This substance has strong single covalent bonds, but weak intermolecular forces 34. Electrons flow in a "sea" throughout the substance 35. Held together by a lattice of positive and negative ions Page 4

5 Base your answers to questions 36 through 39 on the types of solids given below. (A) A metallic solid (B) A molecular solid with hydrogen bonds (C) A molecular solid with non-polar molecules (D) A network solid (E) An ionic solid 36. Which describes solid benzene (C6H6)? 37. Which is described as a lattice of positive ions in a sea of mobile electrons? 38. Which best describes solid water? 39. Which describes diamond (C)? 40. Which compound has the highest boiling point? A) 0.50 molar NaCl B) 0.50 molar NaOH C) 0.50 molar Ca(OH)2 D) 0.50 molar LiOH E) 0.50 molar HBr 41. Based on the above table, which substances are molecular? A) I, II, and VI only B) II, III, and IX only C) III, V, and IX only D) III, VII, and VIII only E) IV, V II, and VIII only 42. CO2 is a gas at room temperature and pressure, while SiO2 melts at about 1700 C. What accounts for this large difference in melting points? A) Si Si bonds are stronger than C C bonds. B) CO2 molecules are nonpolar; SiO2 molecules are polar. C) CO2 is a molecular solid; SiO2 is a network covalent solid. D) The Si O bonds in SiO2 molecules are many times stronger than the C=O bonds in CO2 molecules. E) Si has a larger atomic radius than C. 43. CF4 < CCl4 < CBr4 < CI4 According to the above trend in boiling points, which type of bonding force explains the trend above? A) London dispersion forces B) Covalent bonding forces C) Dipole forces D) Halogen bonding forces E) Hydrogen bonding forces 44. Which of the following substances has the strongest bonds? A) N2 B) O2 C) F2 D) I2 E) Hg2 2+ Page 5

6 45. Which has the smallest force of attraction between its molecules? A) H2 B) NaCl C) I2 D) C2H2 E) MgO 46. According the the above electronegativities, which of the following bonds has the most ionic character? A) B) C) D) E) 47. A solution of Na + ions would be best represented by which picture? A) B) C) D) E) 49. How many milliliters of 11.5-molar HCOOH must be diluted to obtain 23 L of 2.0-molar HCOOH? A) 1000 ml B) 2000 ml C) 3000 ml D) 4000 ml E) 5000 ml 50. The weight of HC2H3O2 (molecular weight 60.0) in 20.0 milliliters of a 2.50-molar solution is A) 2.50 grams B) 3.00 grams C) 6.00 grams D) 25.0 grams E) 30.0 grams 51. Base your answer to the following question on A few drops of the indicator bromothymol blue [HBb] is added to water HBb(aq) + H2O( ) Yellow Blue H3O + (aq) + Bb (aq) Which statement is correct? The addition of A) KOH(aq) causes the [HBb] to increase and the solution to turn yellow. B) HCl(aq) causes the [H3O + ] to decrease and the solution to turn yellow. C) HCl(aq) causes an equilibrium shift toward the reactants and the solution turns blue. D) KOH(aq) causes an equilibrium shift toward the products and the solution turns yellow. E) HCl(aq) causes the [H3O + ] to increase and the solution to turn yellow. 48. Which of the following dissolves in water to form an ionic solution? A) O2 B) SiO2 C) KMnO4 D) C12H22O11 E) CH4 Page 6

7 57. Which is amphiprotic? A) SO3 2 B) NH4 + C) PO4 3 D) HSO3 E) HCl 58. C2O4 2 + MnO2 Mn CO2 52. Based on the above table, list the acids in order of increasing acid strength. A) CH3COOH, NH4 +, HIO3 B) HIO3, CH3COOH,NH4 + C) HIO3,HIO3,CH3COOH D) NH4 +, HIO3, CH3COOH E) NH4 +, CH3COOH, HIO3 As a result of the above reaction, the oxidation number of each C atom is A) decreased by 1 B) increased by 2 C) decreased by 2 D) decreased by 4 E) increased by The oxidation number of sulfur in Na2S2O3 is A) 2 B) +1 C) +2 D) +4 E) If 50 ml of M NaOH is mixed with 50 ml of 0.05 M HCl, what is the resulting ph of the mixture closest to? A) 1 B) 2 C) 3 D) 4 E) According to the table above, which indicator will be yellow at ph 7 and blue at ph 10? A) Thymol blue B) Methyl violet C) Bromothymol blue D) Bromocresol green E) None of these 54. CH3NH2 + H2O CH3NH3 + + OH Which species acts as an acid? I. H2O II. CH3NH3 + III. CH3NH2 A) I only B) II only C) I and II only D) II and III only E) I, II, and III 55. The conjugate base of H2BO3 is A) BO3 3 B) H2BO4 C) H2BO3 D) H3BO3 E) HBO All of the following ions can act as Bronsted-Lowry acids in solution EXCEPT A) HPO4 2 B) H2O C) SO4 2 D) NH4 + E) CH3COOH 61. Given the above values, Which is true about hydronium and hydroxide ion concentrations when water is heated? A) and both remain the same B) and both decrease C) increases and decreases D) decreases and increases E) and both increase 62. The Ka of formic acid is The ph of 1.20 M formic acid (aq) is A) 1.83 B) 12.1 C) 3.75 D) 3.67 E) What is the [H3O + ] of a solution with a poh of 4.60? A) M B) M C) M D) M E) M Page 7

8 64. Solution A: [OH ] = M Solution B: [H + ] = 0.20 M Solution C: poh = Solution D: ph = 1.20 Four monoprotic acids of the same concentration are labeled above. List the four solutions above in order of DECREASING acidity. A) D > B > C > A B) C > D > B > A C) A > B > C > D D) B > D > C > A E) D > C > B > A O2(g) + H2(g) H2O(g) kj 12 O2(g) + 2 H(g) H2O(g) kj Given the above two equations, how much energy is needed to dissociate 1.00 mole of H2 according to the equation below? H2(g) 2H(g) A) 243 kj B) 418 kj C) 661. kj D) 904. kj E) 1320 kj 66. Which of the following reactions has the largest increase in entropy? A) 2 La2O3(s) 3 O2(g) + 4 La(s) B) Cu 2+ (aq) + 2 Ag + (aq) Cu 2+ (aq) + 2 Ag(aq) C) H2(g) + 2 KOH(aq) H2O(l) + 2 K(s) D) 2 CO(g) + O2(g) 2 CO2(g) E) Pb(NO3)2(s) + 2 KI(s) PbI2(s) + 2 KNO3(s) 68. According to the table above, which compound cannot be formed spontaneously from its elements at 298 K? A) A B) B C) C D) D E) All compounds can be formed spontaneously at 298K 69. Which number contains exactly 5 significant digits? A) B) C) D) E) A student calculated the mass of a small piece of unreactive metal. This piece of metal was added to a partially filled graduated cylinder. The following measurements were made by the student: Mass of metal = grams Volume of water before the metal was added= 7.51 milliliters Volume of water after the metal was added= 9.41 milliliters The density of the metal should be reported as A) g/ml B) g/ml C) 7.20 g/ml D) 7.2 g/ml E) 7 g/ml 67. According to the table above, which reactions occur spontaneously? A) II and IV B) II and III C) I and III D) I and IV E) I and II Page 8

9 Answer Key AP 1st Semester Final Review C 2. D 3. A 4. D 5. A 6. C 7. B 8. D 9. C 10. D 11. A 12. D 13. A 14. C 15. B 16. D 17. A 18. D 19. A 20. C 21. C 22. D 23. D 24. A 25. E 26. B 27. C 28. E 29. D 30. C 31. D 32. D 33. E 34. C 35. A 36. C 37. A 38. B 39. D 40. C 41. A 42. C 43. A 44. A 45. A 46. A 47. E 48. C 49. D 50. B 51. E 52. E 53. C 54. C 55. E 56. C 57. D 58. E 59. C 60. B 61. E 62. A 63. E 64. D 65. B 66. A 67. E 68. C 69. E 70. C Page 9