Name AP Chemistry Take Home Quiz Due Thursday, 1/9/2014 Bubble the correct answer on your scantron for each of the following. 1. Barium sulfate is LEAST soluble in a 0.01-molar solution of which of the following? a. Al 2 (SO 4 ) 3 b. (NH 4 ) 2 SO 4 c. Na 2 SO 4 d. NH 3 e. BaCl 2 2. Which of the following compounds is NOT appreciably soluble in water but is soluble in dilute hydrochloric acid? a. Mg(OH) 2 (s) b. (NH 4 ) 2 CO 3 (s) c. CuSO 4 (s) d. (NH 4 ) 2 SO 4 (s) e. Sr(NO 3 ) 2 (s) 3. How many milliliters of water must be added to 10 milliliters of an HCl solution with a ph of 1 to produce a solution with a ph of 3? a. 10 ml b. 90 ml c. 100 ml d. 990 ml e. 1000 ml 4. Which atom in its ground state has the most unpaired electrons? a. Ge b. As c. Se d. Br e. Ga 5. Which of the following is the correct equilibrium expression for the hydrolysis of CO 3 2-? a. K = [HCO 3 - ] / ([CO 3 2- ] [H 3 O + ]) b. K = ([HCO 3 - ] [OH - ] ) / [CO 3 2- ] c. K = ([CO 3 2- ] [OH - ]) / [HCO 3 - ] d. K = [CO 3 2- ] / ([CO 2 ] [OH - ] 2 ) e. K = ([CO 3 2- ] [H 3 O + ]) / [HCO 3 - ] 6. A 1-molar solution of which of the following salts has the highest ph? a. NaNO 3 b. Na 2 CO 3 c. NH 4 Cl d. NaHSO 4 e. Na 2 SO 4 7. HSO 4 - + H 2 O qe H 3 O + + SO 4 2- In the equilibrium represented above, the species that act as bases include which of the following? I. H 2 O II. HSO 4 - III. SO 4 2- a. II only b. III only c. I and II d. I and III e. II and III 8. A sample of 0.0100 mole of oxygen gas is confined at 37 C and 0.216 atmosphere. What would be the pressure of this sample at 15 C and the same volume? a. 0.0876 atm b. 0.175 atm c. 0.201 atm d. 0.233 atm e. 0.533 atm 9. Cr 2 O 7 2- (aq) + 3Sn 2+ (aq) + 14H + (aq) 2Cr 3+ (aq) + 3Sn 4+ (aq) + 7H 2 O Which of the following statements about this reaction is true? a. dichromate ions are oxidized by Sn(II) ions b. hydrogen ions are reduced to H 2 O c. oxygen is reduced from -2 to 0 d. the oxidation state of chromium does not change e. chromium is reduced from the +6 to the +3 oxidation state 10. What is the molar solubility in water of Ag 2 CrO 4? (The K sp for Ag 2 CrO 4 is 8 x 10-12.) a. 8 x 10-12 M b. 2 x 10-12 M c. (4 x 10-12 M) 1/2 d. (4 x 10-12 M) 1/3 e. (2 x 10-12 M) 1/3 11. Which of the following pairs of compounds can be used to illustrate the law of multiple proportions? a. H 2 O and H 2 O 2 b. HCl and HClO 3 c. KBr and KCl d. NH 3 and NH 4 Cl e. AgNO 3 and Ag 2 SO 3
12. Oxygen, which is 16 times as dense as hydrogen, diffuses: a. 1/16 times as fast. b. 1/4 times as fast. c. 4 times as fast. d. 16 times as fast e. equally as fast as hydrogen. 13. The density of an unknown gas is 4.20 grams per liter at 3.00 atmospheres pressure and 127 C. What is the molecular weight of this gas? (R = 0.0821 liter-atm / mole-k) a. 14.6 b. 46.0 c. 88.0 d. 94.1 e. 138 14. A pure sample of KClO 3 is found to contain 71 grams of chlorine atoms. What is the mass of the sample? a. 122 grams b. 170 grams c. 209 grams d. 245 grams e. 293 grams 15. MnS(s) + 2H + <===> Mn 2+ + H 2 S(g) At 25 C the solubility product constant, K sp, for MnS in 5 x 10-15 and the acid dissociation constants K 1 and K 2 for H 2 S are 1 x 10-7 and 1 x 10-13, respectively. What is the equilibrium constant for the reaction represented by the equation above at 25 C? a. 1 x 10-13 / 5 x 10-15 b. 5 x 10-15 / 1 x 10-7 c. 1 x 10-7 / 5 x 10-20 d. 5 x 10-15 / 1 x 10-20 e. 1 x 10-20 / 5 x 10-15 16. 2MnO 4 - + 5SO 3 2- + 6H + 2Mn 2+ + 5 SO 4 2- + 3H 2 O Which of the following statements is true regarding the reaction given above? a. MnO 4 - acts as the reducing agent b. H + acts as the oxidizing agent c. SO 3 2- acts as the reducing agent d. MnO 4 - is oxidized e. SO 3 2- is reduced 17. Equal volumes of 0.10-molar H 3 PO 4 and 0.20-molar KOH are mixed. After equilibrium is established, the type of ion in solution in largest concentration, other than the K + ion, is 2-3- a. H 2 PO 4 b. HPO 4 c. PO 4 d. OH - e. H 3 O + 18. A student examined 2.0 moles of an unknown carbon compound and found that the compound contained 48 grams of carbon, 64 grams of oxygen and 8 grams of hydrogen. Which of the following could be the molecular of the compound? a. CH 2 O b. CH 2 OH c. CH 3 COOH d. CH 3 CO e. C 2 H 5 OH 19. Which of the following will produce a buffered solution? I. Equal volumes of 1 M NH 3 and 1 M HC 2 H 3 O 2 solutions are mixed. II. Equal volumes of 1 M H 2 CO 3 and 1 M KHCO 3 solutions are mixed. III. Equal volumes of 0.1 M NH 3 and 0.1 M NH 4 Cl solutions are mixed. a. I only b. III only c. I and II only d. II and III only e. I, II and III 20. If the acid dissociation constant, K a, for an acid HA is 8 x 10-4 at 25 C, what percent of the acid is dissociated in a 0.50-molar solution of HA at 25 C? a. 0.08% b. 0.2% c. 1% d. 2% e. 4% 21. How much water must be added to a 50.0 ml solution of 0.60 M HNO 3 to produce a 0.40 M solution of HNO 3? a. 25 ml b. 33 ml c. 50 ml d. 67 ml e. 75 ml 22. Each of the following compounds was added to distilled water at 25 c. Which one produced a solution with a ph that was greater than 7? a. N 2 b. O 2 c. NaI d. MgO e. SO 2 23. Which of the following elements forms a polyatomic anion where it has an oxidation number of +6? a. Ca b. S c. Fe d. N e. Cs
24. A sealed isothermal container initially contained 2 moles of CO gas and 3 moles of H 2 gas. The following reversible reaction occurred: CO(g) + 2H 2 (g) qe CH 3 OH(g) At equilibrium, there was 1 mole of CH 3 OH in the container. What was the total number of moles of gas present in the container at equilibrium? a. 1 b. 2 c. 3 d. 4 e. 5 25. What is the volume of 0.05 molar HNO 3 that is required to neutralize 100 ml of a 0.10 molar Ca(OH) 2 solution? a. 100 ml b. 200 ml c. 300 ml d. 400 ml e. 500 ml 26. CH 3 CH 2 OH boils at 78 C and CH 3 OCH 3 boils at - 24 C, although both compounds have the same composition. This difference in boiling points may be attributed to a difference in a. molecular mass b. density c. specific heat d. hydrogen bonding e. heat of combustion 27. HCl(aq) + AgNO 3 (aq) AgCl(s) + HNO 3 (aq) One half liter of a 0.20 molar HCl solution is mixed with one-half liter of a 0.40 molar solution of AgNO 3. A reaction occurs forming a precipitate as shown above. If the reaction goes to completion, what is the mass of AgCl produced? a. 14 grams b. 28 grams c. 42 grams d. 70 grams e. 84 grams 28. When the following half reaction is balanced with the smallest whole number coefficients, it will contain: NO 3 - NO a. 2e - on the right side b. 4e - on the left side c. 2H 2 O on the right side d. 2H + on the left side e. a coefficient of 2 for NO 29. The solubility of CuI is 2 x 10-6 molar. What is the solubility product constant, K sp, for CuI? a. 1.4 x 10-3 b. 2 x 10-6 c. 4 x 10-12 d. 2 x 10-12 e. 8 x 10-18 30. 2 ZnS(s) + 3 O 2 (g) 2 ZnO(s) + 2 SO 2 (g) If the reaction above took place at standard temperature and pressure, what was the volume of O 2 (g) required to produce 40.0 grams of ZnO(s)? (40.0)(2) a. L (81.4)(3)(22.4) (40.0)(3)(22.4) d. L (81.4)(2) (40.0)(3) b. L (81.4)(2)(22.4) (81.4)(2)(22.4) e. L (40.0)(3) 31. What is the percent composition by mass of the elements in the compound NaNO 3? a. Na 20%, N 20%, O 60% b. Na 23%, N 14%, O 48% c. Na 23%, N 14%, O 63% d. Na 27%, N 16%, O 57% e. Na 36%, N 28%, O 36% (40.0)(2)(22.4) c. L 81.4)(3) 32. CH 4 (g) + 2 O 2 (g) CO 2 (g) + 2 H 2 O(l); ΔH = - 889.1 kj ΔH f H 2 O(l) = - 285.8 kj / mole ΔH f CO 2 (g) = - 393.3 kj / mole What is the standard heat of formation of methane, ΔH f CH 4 (g), as calculated from the data above? a. -107.5 kj/mole b. -75.8 kj/mole c. -210.0 kj/mole d. 75.8 kj/mole e. 210.0 kj/mole
33. At constant temperature and pressure, the heats of formation for H 2 O(g), CO 2 (g) and C 2 H 6 (g) are as follows: Species H (kj/mole) H 2 O(g) -251 CO 2 (g) -393 C 2 H 6 (g) -84 If H values are negative for exothermic reactions, what is the H for 1 mole of C 2 H 6 gas to oxidize to carbon dioxide gas and water vapor (temperature and pressure are held constant)? a. -8730 kj/mole b. -2910 kj/mole c. -1455 kj/mole d. 1455 kj/mole e. 2910 kj/mole 34. ph is equal to pk a : a. at the equivalence point of a titration b. when [acid] = [conjugate base] c. in the buffer region d. in the Henderson-Hasselbach equation e. at equilibrium 35. Which of the following is the acid anhydride of a monoprotic acid? a. N 2 O 5 b. SO 3 c. FeO d. CO 2 e. CaO 36. The acid dissociation constant for HClO is 3.0 x 10-8. What is the hydrogen ion concentration in 0.12 M solution of HClO? a. 3.6 x 10-9 M b. 3.6 x 10-8 M c. 6.0 x 10-8 M d. 2.0 x 10-5 M e. 6.0 x 10-5 M Compound K sp at 25 C FeS 6.33 x 10-18 PbS 8.03 x 10-28 MnS 1.03 x 10-13 37. The molecular formula for the hydrated ferric oxide is generally written as Fe 2 O 3 * x H 2 O because the water content in rust can vary. If a 1-molar sample of hydrated ferric oxide is found to contain 108 g of H 2 O, what is the molecular formula of the compound? a. Fe 2 O 3 * H 2 O b. Fe 2 O 3 * 3H 2 O c. Fe 2 O 3 * 6H 2 O d. Fe 2 O 3 * 10H 2 O e. Fe 2 O 3 * 12H 2 O 38. The density of a gas is directly proportional to its a. pressure b. volume c. kinetic energy d. temperature e. molecular velocity 39. Which of the following elements most readily shows the photoelectric effect? a. noble gases b. alkali metals c. halogen elements d. transition metals e. the chalcogens 40. A piece of metal weighing 418.6 grams was put into a boiling water bath. After 10 minutes, the metal was immediately placed in 250.0 grams of water at 40.0 C. The maximum temperature that the system reached was 50.0 C. What is the specific heat of the metal? The specific heat of the water is 4.186 J/g C. a. 0.500 J/g C b. 1.00 J/g C c. 2.00 J/g C d. 4.00 J/g C e. 8.00 J/g C 41. In expanding from 5.00 to 6.00 liters at a constant pressure of 2.00 atmospheres, a gas absorbs 505.64 joules of energy (101.32 J = 1 liter atm). The change in energy E for the gas is: a. 50.66 J b. 101.32 J c. 303.00 J d. 505.64 J e. 606.00 J 42. A solution at 25 C contains Fe 2+, Pb 2+, and Mn 2+ ions. Which of the following gives the order in which precipitates will form, from first to last, as Na 2 S is steadily added to the solution? a. FeS, PbS, MnS b. MnS, PbS, FeS c. FeS, MnS, PbS d. PbS, FeS, MnS e. MnS, FeS, PbS
43. HC 2 H 3 O 2 (aq) + CN - (aq) qe HCN(aq) + C 2 H 3 O 2 - (aq) The reaction represented above has an equilibrium constant equal to 3.7 x 10 4. Which of the following can be concluded from this information? a. CN - (aq) is a stronger base than C 2 H 3 O 2 - (aq) b. HCN(aq) is a stronger acid than HC 2 H 3 O 2 (aq) c. The conjugate base of CN - (aq) is C 2 H 3 O 2 - (aq) d. The equilibrium constant will increase with an increase in temperature. e. The ph of a solution containing equimolar amounts of CN - (aq) and HC 2 H 3 O 2 (aq) is 7.0. 44. Given a molecule with the general formula AB 2, which one of the following would be the most useful in determining whether the molecule was bent or linear? a. ionization energies b. electron affinities c. dipole moments d. electronegativities e. bond energies 45. For a certain reaction at 298K, the value of K is 1.2 x 10-3. At 323K the value of K is 3.4 x 10-1. This means that the reaction is: a. endothermic. b. exothermic. c. never favorable. d. More information is needed. e. None of these. 46. 6.0 moles of chlorine gas are placed in a 3.0 L flask at 1250 K. At this temperature, the chlorine molecules begin to dissociate into chlorine atoms. What is the value of K c, if 50.% of the chlorine molecules dissociate when equilibrium has been achieved? a. 1.0 b. 3.0 c. 4.0 d. 6.0 e. 12.0 47. A gaseous mixture containing 7.0 moles of nitrogen, 2.5 moles of oxygen, and 0.50 mole of helium exerts a total pressure of 0.90 atmosphere. What is the partial pressure of the nitrogen? a. 0.13 atm b. 0.27 atm c. 0.63 atm d. 0.90 atm e. 6.3 atm 48. Sulfur trioxide gas dissociates into sulfur dioxide gas and oxygen gas at 1250 C. In an experiment 3.60 moles of sulfur trioxide were placed into an evacuated 3.0 L flask. The concentration of sulfur dioxide gas measured at equilibrium was found to be 0.20 M. What is the equilibrium constant K c, for the reaction? a. 1.6 x10-4 b. 1.0 x 10-3 c. 2.0 x 10-3 d. 4.0 x 10-3 e. 8.0 x 10-3 49. It takes 40.0 ml of 0.100 M NaOH to titrate 488 mg of a solid monoprotic acid to the phenolphthalein endpoint. What is the molecular mass of the acid? a. 221 b. 122 c. 68 d. 1.2 x 10 5 e. 1.2 x 10-1 50. When excess hydroxide ions were added to 1.0 liter of CaCl 2 solution, Ca(OH) 2 precipitate was formed. If all the calcium ions in the solution were precipitated in 7.4 grams of Ca(OH) 2, what was the initial concentration of the CaCl 2 solution? a. 0.05 molar b. 0.10 molar c. 0.15 molar d. 0.20 molar e. 0.30 molar 51. How many grams of carbon are present in 270. grams of glucose, C 6 H 12 O 6? a. 12.0 grams b. 18.0 grams c. 67.5 grams d. 72.0 grams e. 108 grams 52. What is the weight of NaNO 3 (molecular weight 85.0) present in 100. ml of a 4.00 molar solution? a. 8.50 grams b. 17.0 grams c. 25.5 grams d. 34.0 grams e. 51.0 grams 53. A method of separation where a mobile phase is passed through a stationary phase is called: a. distillation b. decanting c. filtration d. electrolysis e. chromatography 54. The equilibrium constant for the reaction: CO(g) + H 2 O(g) qe CO 2 (g) + H 2 (g) is 26 at 50ºC. What is the K c for 3CO 2 (g) + 3H 2 (g) qe 3CO(g) + 3H 2 O(g) at the same temperature? a. 0.34 b. 1.8 x 10 4 c. 0.038 d. 5.7 x 10-5 e. 2.9
55. 100 grams of O 2 (g) and 100 grams of He(g) are in separate containers of equal volume. Both gases are at 100ºC. Which of the following statements is true? a. Both gases would have the same pressure. b. The average kinetic energy of the O 2 molecules is greater than that of the He molecules. c. The pressure of the He(g) would be greater than that of the O 2 (g). d. There are equal numbers of He molecules and O 2 molecules. e. The average kinetic energy of the He molecules is greater than that of the O 2 molecules. 56. A 3.00-liter flask initially contains 1.50 mol of gas A and 0.450 mol of gas B. Gas A decomposes according to the following reaction: 3A qe 2B + C The equilibrium concentration of gas C is 0.100 mol/l. Determine the equilibrium concentration of gas A. a. 0.500 M b. 0.100 M c. 0.300 M d. 0.200 M e. none of these 57. The K a for hydrofluoric acid is 6.8 x 10-4. What percentage of HF is dissociated in a 0.080 M solution where the hydronium ion concentration is 7.4 x 10-3 M? a. 1.12% b. 4.25% c. 9.2 % d. 12.3% e. 23.6% 58. A molecule or an ion is classified as a Lewis acid if it a. accepts a proton from water b. accepts a pair of electrons to form a bond c. donates a pair of electrons to form a bond d. donates a proton to water e. has resonance Lewis electron-dot structures 59. How many moles of NaF must be dissolved in 1.00 liter of a saturated solution of PbF 2 at 25 C to reduce the [Pb 2+ ] to 1 x 10-6 molar? (K sp of PbF 2 at 25 C = 4.0 x 10-8 ) a. 0.020 mole b. 0.040 mole c. 0.10 mole d. 0.20 mole e. 0.40 mole 60. Which of the following cannot be a reducing agent? a. Ag b. I - c. Fe 3+ d. Cr 3+ e. Cl - 61. How many grams of NaOH (molar mass = 40.0 g/mol) are contained in 5.00 x 10 2 ml of a 0.80 M sodium hydroxide solution? a. 16 g b. 80. g c. 20. g d. 64 g. e. none of these 62. Which of the following statements is correct? a. HClO 2 is a stronger acid than HClO 3 b. HI is a weaker acid than HCl c. H 3 PO 4 is a stronger acid than HClO 4 d. HNO 3 is a stronger acid than HNO 2 e. CH 3 COOH is a stronger acid than CH 2 BrCOOH 63. Which of the following statements correctly describes the signs of q and w for the following exothermic process at P = 1 atm and T = 370 K? H 2 O(g) H 2 O(l) a. q is negative, w is positive b. q and w are negative c. q and w are both positive d. q is positive, w is negative e. q and w are both zero. 64. The compound that contains 10.4% oxygen is: a. NaOH b. CaO c. Al 2 O 3 d. BaO e. Ca(OH) 2 65. A halogen, X, and an alkaline earth metal, M, can form a compound with the formula: a. MX b. MX 2 c. MX 3 d. M 2 X 3 e. M 3 X 2 66. The K a of hydrocyanic acid, HCN, is 5.0 10 10. What is the ph of 0.050 M HCN(aq)? a. below 3.5 b. between 3.5 and 4.5 c. between 5.0 and 5.5 d. between 9.0 and 9.5 e. between 10.5 and 11.0