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Final Exam Question Bank: 1. __________ A piece of calcite has a mass of 35.6 grams and a volume of 12.9 cm3. On which of the following liquids will calcite float? (A) carbon tetrachloride (density = 1.60 g/cm3) (B) methylene bromide (density = 2.50 g/cm3) (C) neither of the above substances (D) both of the above substances 2. __________ A fish tank measures 48.0 inches long, 12.0 inches deep and 21.0 inches high. How many gallons of water does it hold? (A) 52.4 gallons (B) 8.11 gallons (C) 198 gallons (D) 12.1 gallons 3. __________ Dew forms of a cold glass of water as water vapor in air condenses on the outside of the glass. Condensation can be considered an: (A) endothermic chemical change (B) endothermic physical change (C) exothermic chemical change (D) exothermic physical change 4. __________ A student finds the density of lead to equal 10.59 g/mL. The actual density of lead is 11.34 g/mL. Calculate the student’s percent error? (A) 7.5% (B) 7.1% (C) 6.6% (D) 5.5% 5. __________ Gamma decay produces radiation with a wavelength of 1 x 10-12 meters. What is this distance in micrometers? (A) 1 x 10-6 micrometers (B) 1 x 10-9 micrometers -15 (C) 1 x 10 micrometers (D) 1 x 10-18 micrometers 6. __________ Which of the following is an example of a chemical change to a pure substance? (A) oxidation of 26.0 grams of lead (B) sublimation of carbon dioxide (C) freezing of 26.0 grams of a calcium chloride solution (D) melting of gallium in your hand 7. __________ Which of the following is an extensive property? (A) very ductile (B) volume of 4.3 L (C) density of 3.4 g/mL (D) poor conductor of heat 8. __________ Which of the following measurements shows good precision & poor accuracy and systematic error, if the actual scientific value is 3.74 cm? (A) 2.75 cm, 3.75 cm , 4.05 cm (B) 3.76 cm, 3.76 cm, 3.75 cm (C) 4.02 cm, 4.02 cm, 4.01 cm (D) 4.52 cm. 4.78 cm, 4.01 cm 9. __________ Which separation technique would be used to separate the colors in a mixture? (A) decanting (B) magnetism (C) distillation (D) chromatography 10. __________ How many total significant figures would the solution to the following calculation have? 421.3 + 0.005 + 510. (A) 1 (B) 2 (C) 3 (D) 4 11. __________ Some bottles of colorless liquids were being labeled when the technicians accidentally mixed them up and lost track of their contents. A 24.8 mL sample withdrawn from one bottle weighed 22.3 g. Which of the following is the correct identity of the unknown liquid? (A) acetone, d=0.792 g/mL (B) benzene, 0.899 g/mL (C) chloroform, d=1.489 g/mL (D) carbon tetrachloride, d=1.595 g/mL 12. __________ The proper scientific notation for 56,500,000,000 is — (A) 0.565 x 1011 (B) 5.65 x 1010 (C) 5.65 x 10-10 (D) 565 x 10-8 13. __________ Deposition is an example of an: (A) exothermic chemical change (C) endothermic chemical change (B) endothermic physical change (D) exothermic physical change 14. __________ A student is given a container of potassium nitrate crystals. In order to determine the exact mass of the potassium nitrate using a balance, he must know the — (A) mass of the filled container and the chemical formula for potassium nitrate (B) mass of the filled container and the density of potassium nitrate (C) volume of the filled container and the volume of the potassium nitrate (D) mass of the empty container and the mass of the filled container 15. __________ The density values for 4 substances are given: Benzene (0.880 g/mL), Ethanol (0.789 g/mL), Water (0.9982 g/mL) and Mercury (13.6 g/mL). If you had 10.0 mL of each substance, which would have the greatest mass? (A) ethanol (B) benzene (C) mercury (D) water 16. __________ Which of the following would have an answer with three significant figures? (A) 103.1 + 0.0024 + 0.16 (B) (3.0 x 104)(5.022 x 10-3) / (6.112 x 102) 5 (C) (4.3 x 10 ) / (4.225 + 56.0003 – 0.8700) (D) (1.43 x 103 + 3.1 x 101) / (4.11 x 10-6) 17. __________ Mass of an empty container = 3.0 grams Mass of the container plus the solid sample = 25.0 grams Volume of the solid sample = 11.0 cubic centimeters The data above were gathered in order to determine the density of an unknown solid. The density of the sample should be reported as: (A) 0.5 g/cm3 (B) 0.50 g/cm3 (C) 2.0 g/cm3 (D) 2.00 g/cm3 18. __________A method of separation where a mobile phase is passed through a stationary phase is called: (A) distillation (B) decanting (C) using a magnet (D) chromatography 19. __________Which of the following experimental procedures is used to separate two substances by taking advantage of their boiling points? (A) chromatography (B) distillation (C) filtration (D) decanting 20. __________If the actual scientific value is 1.57 grams/mL, which of the following sets of results shows poor accuracy, good precision and high systematic error? (A) 1.68 g/mL, 1.68 g/mL, 1.68 g/mL (B) 1.57 g/mL, 1.57 g/mL, 1.57 g/mL (C) 1.68 g/mL, 1.57 g/mL, 1.49 g/mL (D) 1.58 g/mL, 1.57 g/mL, 1.56 g/mL 21. __________ What is the maximum number of electrons that occupy the n = 2 level? (A) 32 (B)18 (C) 10 (D) 8 (E) 6 22. __________ 191Re (rhenium-191) produces a beta particle during decay. What is the other product of the reaction? (A) 191W (B) 190Os (C) 190W (D) 192Pt (E) 191Os 23. __________ Which type of radiation is attracted to a positive electric field? (A) alpha (B) gamma (C) positron (D) proton (E) beta 24. __________ The half-life for electron capture for 40K is 1.30 x 109 years. What percent of the original 40K remains after 3.90 x 109 years? (A) 33.3% (B) 50.0% (C) 12.5% (D) 75.0% (E) 25.0% 25. __________ The cathode ray tube was instrumental in the discovery of the: (A) electron (B) neutron (C) proton (D) nucleus (E) atom being mostly empty space 26. __________ Which of the following is an acceptable set of quantum numbers for the highest energy orbital of rubidium's valence orbital? (A) 1,5,0, -½ (B) 5,1,0,+½ (C) 1,5,-3,+½ (D) 5,0,-1,+½ (E) 5,0,0, -½ 27. __________ An oxygen atom has 8 electrons. How many of these electrons are in s orbitals? (A) 2 (B) 4 (C) 6 (D) 8 (E) none 28. __________ 251 98 Cf 1 20n + 131 54 Xe + _____ What is the missing product in the nuclear reaction represented above? (B) 118Ru (C) 120Mo (D) 120Ru (E) 122Pd (A) 118Mo 29. __________ The nuclide is: (A) 245 94 Pu (B) 245 95 Am 245 96 Cm is radioactive and decays by the loss of one beta particle. The product nuclide (C) 248 96 Cm (D) 250 96 Cm (E) 245 97 Bk 30. __________ Which symbol represents the atom with the largest number of neutrons? (B) 238U (C) 208Pb (D) 226Ra (E) 237Np (A) 234Th 31. __________ How many orbitals are there in the third energy level? (A) 3 (B) 4 (C) 9 (D) 18 (E) 28 32. __________ How many orbitals in a ground state fluorine atom are completely filled? (A) 5 (B) 4 (C) 3 (D) 2 (E) 1 33. __________ In Bohr’s atomic theory, when an electron moves from one energy level to another energy level more distant from the nucleus: (A) light is emitted (B) energy is emitted (C) energy is absorbed (D) no change in energy occurs (E) none of these Use the following answers for questions 34-35. (A) 1s2 2s2 2p5 3s2 3p5 (B) 1s2 2s2 2p6 3s2 3p6 3d3 4s2 (C) 1s2 2s2 2p6 3s2 3p6 (D) 1s2 2s2 2p6 3s2 3p6 3d5 (E) 1s2 2s2 2p6 2d10 3s2 3p6 34. __________ The ground-state configuration of a noble gas. 35. __________ An impossible electronic configuration 36. ___________ Which of the following has the largest value for the third ionization energy? (A) carbon (B) fluorine (C) oxygen (D) boron (E) beryllium 37. ___________ Which of the following metal ions would have the largest ionic radius? (A) Mn2+ (B) Cr2+ (C) Fe2+ (D) Cu2+ (E) Zn2+ 38. ___________ Which of the following has the largest atomic radius? (A) P2(B) P5+ (C) P3(D) P3+ (E) P Ionization Energies for element X (kJ mol-1) First Second Third Fourth Five 738 1451 7733 10540 13630 39. ___________ The ionization energies for element X are listed in the table above. On the basis of the data, element X is most likely to be: (A) Na (B) Mg (C) Al (D) Si (E) P 40. ___________ Calcium has an atomic radius of 194 pm and a first ionization energy of 590 kJ/mol. Based on periodic trends, which of the following are the most probable values of the atomic radius and the first ionization energy for potassium, respectively? (A) 242 pm, 633 kJ (B) 120 pm, 633 kJ/mol (C) 120 pm, 419 kJ/mol (D) 242 pm, 419 kJ/mol (E) none of these are probable 41. ___________ Which of the following represents the ground state electron configuration for the Mn2+ ion? (A) 1s22s22p63s23p64s23d3 (B) 1s22s22p63s23p64s23d7 (C) 1s22s22p63s23p63d5 2 2 6 2 6 8 1 2 2 6 2 (D) 1s 2s 2p 3s 3p 3d 4s (E) 1s 2s 2p 3s 3p63d7 42. ___________ In which of the following are the elements listed in order of increasing first ionization energy? (A) Al, Mg, P, Ar (B) Li, Be, B, F (C) Ba, B, Bi, Br (D) Ar, Cl, P, Na (E) P, S, Cl, Ar 43. ___________ Which of the following elements will release the most energy when it gains an electron? (A) helium (B) beryllium (C) nitrogen (D) radon (E) chlorine 44. ___________ Which element has the largest first ionization energy? (A) Li (B) B (C) N (D) Na (E) O 45.__________ Which of the following contains an element with a +1 oxidation number? (A) CaO (B) PbCl4 (C) AlP (D) Cu2O (E) TiN 46. __________ Which of the following would likely have the highest melting point? (A) MnCl2 (B) MnCl3 (C) MnCl4 (D) MnCl6 (E) MnCl7 47. __________ What is the oxidation number of phosphorus in magnesium phosphate? (A) -3 (B) +3 (C) +4 (D) +5 (E) -5 48. __________ Which ionic compound has the lowest melting point? (The other test asked HIGHEST melting point.) (A) KCl (B) K2O (C) CaCl2 (D) CaO (E) CaF2 49. __________ Which of following is true for ionic compounds but false for metals? (A) They are malleable. (B) Their solid form can conduct electricity. (C) They have free moving electrons. (D) They are arranged in a crystalline structure. (E) Their valence electrons are attached to only one atom. 50. __________ What is the oxidation number of vanadium in V(CrO4)2? (A) +2 (B) -2 (C) +1 (D) +4 (E) +6 51. __________Which of the following solids can conduct electricity at room temperature? I. Ag II. Ag2O III. AgOH (A) I only (B) I and II only (C) I and III only (D) II and III only (E) I, II, and III 52. __________When LiF is formed from its elements there are five steps. Which of the following steps are endothermic? They are not listed in order below. Dissociation of fluorine molecules. ½ F2(g) F(g) Formation of LiF from Li+(g) and F-(g) ions. Li+(g) + F-(g) LiF(s) Sublimation of solid lithium. Li(s) Li(g) Ionization of lithium atom. Li(g) Li+(g) + eFormation of fluoride ions. F(g) + e- F-(g) (A) I, II & III only (B) I, III & V only (C) I, III & IV only (D) II & V only (E) none of these 53. _________ To make Au stronger and Element Metallic Radius Melting Point Common harder, it is often alloyed with other metals, (pm) (°C) Oxidation State such as Cu and Ag. Au 144 1064 1+, 3+ Consider two alloys, one of Au and Cu and Cu 128 1085 1+, 2+ one of Au and Ag, each with the same Ag 144 961 1+ mole fraction of Au. If the Au/Cu alloy is harder than the Au/Ag alloy, then which of the following is the best explanation based on the information in the table above? (A) Cu has two common oxidation states, but Ag has only one. (B) Cu has a higher melting point than Au has, but Ag has a lower melting point than Au has. (C) Cu atoms are smaller than Ag atoms, thus they interfere more with the displacement of atoms in the alloy. (D) Cu atoms are less polarizable than are Au or Ag atoms, thus Cu has weaker interparticle forces. (E) None of the above explain why the Au/Cu alloy is harder than the Au/Ag alloy. 54. __________ What is the oxidation number of chromium in iron(III) dichromate? (A) +3 (B) -3 (C) +6 (D) -2 (E) +12 Use these answers for questions 55-59. Answers may be used more than once. (A) hybridization (B) ionic bonding (C) hydrogen bonding (D) resonance (E) London dispersion forces 55._______________Is used to explain the fact that the carbon-to-oxygen bonds in carbonate are identical 56._______________Is used to explain the fact that sodium chloride is a solid at room temperature 57._______________Is used to explain why iodine molecules are held together in the solid state 58._______________Is used to explain the fact that the four bonds in methane are equivalent 59._______________Is used to explain why the boiling point of HF is greater than the boiling point of HBr 60._______________ I. NO II. SF2 III. PF4+ Which species have one or more atoms that violate the octet rule? (A) I and II only (B) III only (C) I only (D) I, II &III (E) I and III only 61._______________The bonding in carbon monosulfide consists of: (A) 1 sigma bond and 2 pi bonds (B) 2 sigma bonds and 1 pi bond (C) 3 sigma bonds (D) 3 pi bonds (E) 1 sigma and 1 pi bond 62._______________Pi bonding occurs in each of the following species EXCEPT (A) CO2 (B) CO32(C) HCN (D) SeO2 (E) CCl2F2 63._______________Which liquid is most volatile at 25°C? (A) butane, C4H10 (B) glycerol, C3H5(OH)3 (C) octane, C8H18 (D) propanol, C3H7OH (E) nonane, C10H22 64._______________Which of the following atoms is diamagnetic? (A) sodium (B) chlorine (C) magnesium (D) aluminum (E) sulfur 65._______________Which species has the smallest Cl-A-Cl bond angle where A is the central atom? (A) SCl6 (B) CCl4 (C) NCl3 (D) OCl2 (E) BCl3 66._______________If a sulfur trioxide molecule is drawn so that the formal charge on each atom is zero, it will have the following types of bonds: (A) 3 sigma and 0 pi (B) 3 sigma and 1 pi (C) 3 sigma and 2 pi (D) 3 sigma and 3 pi (E) 3 sigma and 6 pi 67._______________ Which of the following atoms is the most paramagnetic? (A) sodium (B) chlorine (C) magnesium (D) aluminum (E) sulfur Use these answers for questions 68 - 70. (A) NO (B) SO2 (C) CaO (D)CBr4 (E) CO2 68._______________Which of the molecules has four sp3 hybrid bonds? 69._______________Which substance would have the greatest melting point? 70._______________In which of the choices is there polar double bonding in a non-polar molecule? 71. ________________. . .C10H12O4S(s) + . . O2(g) . . . CO2(g) + . . . SO2(g) + . . . H2O(g) When the equation above is balanced and all coefficients are reduced to their lowest whole-number terms, the coefficient for O2(g) is? (A) 6 (B) 7 (C) 12 (D) 14 (E) 28 72. ________________ ... Fe(OH)2 + ... O2 + ... H2O ... Fe(OH)3 If 1 molecule of O2 oxidizes Fe(OH)2 according to the reaction represented above, how many moles of Fe(OH)3 can be formed? (A) 2 (B) 3 (C) 4 (D) 5 (E) 6 73. ________________A yellow precipitate forms when 0.5 M NaI(aq) is added to a 0.5 M solution of which of the following ions? (A) Pb2+(aq) (B) K+(aq) (C) CrO42- (aq) (D) SO42- (aq) (E) OH- (aq) 74. ________________. . . Li3N(s) + . . . H2O(l) . . . Li+ (aq) + . . . OH-(aq) + . . . NH3(g) When the equation above is balanced and all coefficients reduced to lowest whole number terms, the coefficient for OH- (aq) is (A) 1 (B) 2 (C) 3 (D) 4 (E) 6 75.________________ 6 I¯ + 2 MnO4¯ + 4 H2O(l) 3 I2(s) + 2 MnO2(s) + OH¯ Which of the following statements regarding the reaction represented by the equation above is correct? (A) Iodide ion is oxidized by hydroxide ion. (B) MnO4¯ is oxidized by iodide ion. (C) The oxidation number of manganese changes from +7 to +2. (D) The oxidation number of manganese remains the same. (E) The oxidation number of iodine changes from -1 to 0. 76. ________________ __ CH3CH2COOH(l) + __ O2(g) __ CO2(g) + __ H2O(l) How many moles of O2 are required to oxidize 1 molecule of CH3CH2COOH according to the reaction represented above? (A) 2 moles (B) 5/2 moles (C) 3 moles (D) 7/2 moles (E) 9/2 moles Questions 77–79 refer to the reactions represented below. – + (A) H2SeO4(aq) + 2 Cl (aq) + 2 H (aq) H2SeO3(aq) + Cl2(g) + H2O(1) (B) S8(s) + 8 O2(g) 8 SO2(g) – – (C) 3 Br2(aq) + 6 OH (aq) (D) Ca (aq) + SO4 (aq) CaSO4(s) PtCl4(s) + 2 Cl (aq) PtCl6 (aq) (E) 2+ 2– – – 5 Br (aq) + BrO3 (aq) + 3 H2O(l) 2– 77. ________________ A combustion reaction 78. ________________ A precipitation reaction 79. ________________ A reaction in which the same reactant undergoes both oxidation and reduction + 2+ 80. ________________ 3 Cu(s) + 8 H (aq) + 2 NO3-(aq) 3 Cu (aq) + 2 NO(g) + 4 H2O(l) True statements about the reaction represented above include which of the following? I. Cu(s) acts as an oxidizing agent. II. The oxidation state of nitrogen changes from +5 to +2. III. Hydrogen ions are oxidized to form H2O(l). (A) I only (B) III only (C) II only (D) I and II (E) II and III 81. ________________ Ca3(PO4)2 + H3PO4 Ca(H2PO4)2 When the equation above is balanced and all coefficients are reduced to lowest whole number terms, what is the coefficient for H3PO4? (A) 1 (B) 2 (C) 3 (D) 4 (E) 5 82. ________________ Propane gas, C3H8, burns in excess oxygen gas. When the equation for this reaction is correctly balanced and all coefficients are reduced to their lowest whole-number terms, the coefficient for O2 is (A) 4 (B) 5 (C) 7 (D) 10 (E) 22 83. ________________Which of the following substances is LEAST soluble in water? (A) (NH4)2SO4 (B) BaCO3 (D) Zn(NO3)2 (C) KMnO4 (E) Na3PO4 Questions 84-85 refer to the chemical reactions represented below. (A) HC2H3O2(aq) + NH3(aq) → C2H3O2−(aq) + NH4+(aq) (B) Ba2+(aq) + SO42−(aq) → BaSO4(s) (C) Zn(OH)2(s) + 2 OH−(aq) → [Zn(OH)4]2−(aq) (D) 2 K(s) + Br2(l) → 2 KBr(s) (E) N2O4(g) → 2 NO2(g) 84. ________________ A precipitation reaction 85. ________________ An oxidation-reduction reaction 86. ________________ 2HClO + 3O2 → 2HClO4 As the reaction represented above proceeds to the right, the oxidation number of chlorine changes from: (A) −1 to +3 (B) −1 to +5 (C) +1 to +5 (D) +1 to +7 (E) +3 to +7 87. ________________ . . . CH3OCH3(g) + . . . O2(g) → . . . CO2(g) + . . . H2O(g) When the equation above is balanced using the lowest whole number coefficients, the coefficient for O2(g) is: (A) 6 (B) 4 (C) 3 (D) 2 (E) 1 88. ________________. . . Au3+(aq) + . . . I−(aq) → . . . Au(s) + . . . I2(s) When the equation above is balanced using the lowest whole number coefficients, the coefficient for I2(s) is: (A) 8 (B) 6 (C) 4 (D) 3 (E) 2 89.________________ To determine the percentage of water in a hydrated salt, a student heated a 1.2346 g sample of the salt for 30 minutes; when cooled to room temperature, the sample weighed 1.1857 g. After the sample was heated for an additional 10 minutes and again cooled to room temperature, the sample weighed 1.1632 g. Which of the following should the student do next? (A) Use the smallest mass value to calculate the percentage of water in the hydrated salt. (B) Repeat the experiment with a new sample of the same mass and average the results. (C) Repeat the experiment with a new sample that has a different mass. (D) Reheat the sample until its mass is constant. (E) Use the average of the mass values obtained after the two heatings to calculate the percentage of water in the hydrated salt. 90.________________ What is the maximum number of moles of Al2O3 that can be produced by the reaction of 0.40 mol of Al with 0.40 mol of O2? (A) 0.10 mol (B) 0.20 mol (C) 0.27 mol (D) 0.33 mol (E) 0.40 mol 91.________________ The simplest formula for an oxide of nitrogen that is 25.9 percent nitrogen by weight is (A) N2O (B) NO (C) NO2 (D) N2O3 (E) N2O5 92.________________ Cu2O(s) + H2(g) 2 Cu(s) + H2O (l) What mass of Cu(s) would be produced if 0.40 mol of Cu2O (s) was reduced completely with excess H2 (g)? (A) 13 g (B) 25 g (C) 38 g (D) 51 g (E) 100 g 93.________________ A sample of a compound contains 3.21 g of sulfur and 11.4 g of fluorine. Which of the following represents the empirical formula of the compound? (A) SF2 (B) SF3 (C) SF4 (D) SF5 (E) SF6 94.________________ CS2(l) + 3 O2(g) CO2(g) + 2SO2(g) When 0.60 mol of CS2(l) reacts as completely as possible with 1.5 mol of O2 (g) according to the equation above, the total number of moles of reaction products is: (A) 1.0 mol (B) 0.40 mol (C) 1.8 mol (D) 1.5 mol (E) 4.5 mol 95.________________ A compound contains 29.7% sulfur and 70.3% fluorine by mass. The empirical formula of the compound is: (A) SF (B) SF2 (C) SF4 (D) SF6 (E) S2F 96.________________ How many carbon atoms are contained in 1.4 grams of C2H4? (B) 3.0 x 1022 (C) 6.0 x 1022 (D) 1.2 x 1023 (E) 6.0 x 1023 (A) 1.2 x 1022 97.________________ 8H2(g) + S8(s) 8H2S(g) When 25.6 g of S8(s) reacts completely with an excess of H2(g) according to the equation above, the volume of H2S(g) at STP is closest to: (A) 17.9 L (B) 27.2 L (C) 205 L (D) 143 L (E) 2.24 L 98.________________ What is the empirical formula of a hydrocarbon that is 10.0% hydrogen by mass? (A) CH3 (B) C2H5 (C) C3H4 (D) C4H9 (E) C9H10 99.________________ If 0.40 mol of H2 and 0.15 mol of O2 were to react as completely as possible to produce H2O, what mass of reactant would remain? (A) 0.20 g of H2 (B) 0.40 g of H2 (C) 0.60 g of H2 (D) 4.0 g of O2 (E) 2.0 g of O2 100.________________ The diagram to the right represents H2(g) and N2(g) in a closed container. Which of the following diagrams would represent the results if the reaction shown below were to proceed as far as possible? N2(g) + 3H2(g) 2NH3(g) 101.________________ A compound contains 1.36 mol of Cr, 2.04 mol of S, and 8.16 mol of O. What is the simplest formula of this compound? (B) Cr2(SO3)3 (C) Cr2(SO4)3 (D) CrSO3 (E) CrSO4 (A) Cr(SO3)3 102.________________ What number of moles of O2 is needed to produce 14.2 grams of P4O10 from P? (A) 0.0500 mole (B) 0.0625 mole (C) 0.125 mole (D) 0.250 mole (E) 0.500 mole 103.________________ A 88.0-gram sample of an unknown hydrocarbon was burned in excess oxygen to form 264.0 grams of carbon dioxide and 144.0 grams of water. What is a possible molecular formula of the hydrocarbon? (A) CH4 (B) C3H8 (C) C5H10 (D) C4H6 (E) CH3 104.________________ How many sodium ions are there in 25.0 grams of sodium carbonate? (A) 0.236 Na+ (B) 0.472 Na+ (C) 2.84 x 1023 Na+ (D) 1.42 x 1023 Na+ (E) 6.55 x 1023 Na+ 105.________________ What is the percentage of water in strontium chloride dihydrate? (A) 81.5% (B) 18.5% (C) 89.8% (D) 10.2% (E) 22.3% 106.________________ A hydrated ionic sample is found to be 86.7% Mo2S5 and 13.3% H2O. How many water molecules does the empirical formula of the hydrated compound contain? (A) 2 (B) 3 (C) 4 (D) 5 (E) 6 107.________________. How many grams of calcium nitrate, Ca(NO3)2, contains 55 grams of oxygen atoms? (A) 94 grams (B) 330 grams (C) 68 grams (D) 32 grams (E) 560 grams 108.________________ 2 KClO3(s) 2 KCl(s) + 3 O2(g) What is the percentage yield of O2 if 12.3 g of KClO3 is decomposed to produce 3.2 g of O2 according to the equation above? (A) 100% (B) 67% (C) 50% (D) 33% (E) 10% 109.________________ A compound is analyzed and found to be 49.5% C, 28.9% N, 5.2% H & 16.5% O. The molecular mass of the compound is 194.2 g/mol. Determine its molecular formula. (A) C7N3H4O4 (B) C7N5H8O2 (C) C8N3H8O3 (D) C9N3H12O2 (E) C8N4H10O2 110. _____________ If an endothermic reaction is spontaneous at 298 K, which of the following must be true for the reaction? I. ∆G is greater than zero II. ∆H is greater than zero. III. ∆S is greater than zero. (A) I only (B) II only (C) I & II only (D) II & III only (E) I ,II & III 111. _____________ When pure sodium is placed in an atmosphere of chlorine gas, the following spontaneous reaction occurs. 2Na(s) + Cl2(g) 2NaCl(s) Which of the following statements is true about the reaction? I. ∆S > 0 II. ∆H < 0 III. ∆G > 0 (A) I only (B) II only (C) I & II only (D) II & III only (E) I ,II & III 112. _____________ 2S (s) + 3O2 (g) 2SO3(g) ∆H = +800 kJ/mol 2SO2(g) + O2(g) 2SO3 (g) ∆H = +200 kJ/mol Based on the information given above, what is the ∆H for the following reaction? S(s) + O2(g) SO2(g) (A) 300 kJ (B) 500 kJ (C) 600 kJ (D) 1000 kJ (E) 1200 kJ 113. _____________ Which of the following reactions has the largest positive value of ∆S per mole of Cl2 (A) H2(g) + Cl2(g) 2 HCl(g) (B) Cl2(g) + ½ O2(g) Cl2O(g) (C) Mg(s) + Cl2(g) MgCl2(s) (D) 2 NH4Cl(s) N2(g) + 4 H2(g) + Cl2(g) (E) Cl2(g) 2 Cl(g) 114. _____________ For which of the following processes would ∆S have a negative value? I. 2 Fe2O3(s) 4 Fe(s) + 3 O2(g) II. Mg2+(aq) + 2 OH-(aq) Mg(OH)2(s) III. H2(g) + C2H4(g) C2H6(g) (A) I only (B) I and II only (D) II and III only (C) I and III only (E) I, II, and III 115. _____________ When solid ammonium chloride, NH4Cl(s) is added to water at 25 °C, it dissolves and the temperature of the solution decreases. Which of the following is true for the values of ∆H and ∆S for the dissolving process? ΔH ΔS (A) Postive Positive (B) Positive Negative (C) Positive Equal to zero (D) Negative Positive (E) Negative Negative 116. _____________ 3 C2H2(g) qe C6H6(g) What is the standard enthalpy change, ∆H˚, for the reaction represented above? (∆H˚f of C2H2(g) is 230 kJ mol-1; ∆H˚f of C6H6(g) is 83 kJ mol-1.) (A) –607 kJ (B) –147 kJ (C) –19 kJ (D) +19 kJ (E) +773 kJ 117. _____________ For the reaction, N2H4(l) N2(g) + 2H2(g) ΔH° = -50.6 kJ. This reaction is: (A) spontaneous at all temperatures. (B) non-spontaneous at all temperatures. (C) spontaneous only at low temperatures. (D) spontaneous only at high temperatures. (E) there is not enough information to make a decision. 118. _____________ The ΔH° and ΔS° values for a particular reaction are –60.0 kJ and –0.200 kJ·K–1 respectively. Under what conditions is this reaction spontaneous? (A) all conditions (B) T < 300 K (C) T = 300 K (D) T > 300 K (E) there is not enough information to make a decision. 119. _____________ Under which of the following conditions can an endothermic reaction be thermodynamically favorable? (A) ΔG is positive (B) ΔS is negative (C) TΔS > ΔH (D) TΔS = 0 (E) There are no conditions under which an endothermic reaction can be thermodynamically favorable. 120. _____________ C(diamond) → C(graphite) For the reaction represented above, the standard Gibbs free energy change, ΔG°298, has a value of −2.90 kJ mol−1. Which of the following best accounts for the observation that the reaction does NOT occur (i.e., diamond is stable) at 298 K? (A) ΔS° for the reaction is positive. (B) The activation energy, Ea, for the reaction is very large. (C) The reaction is slightly exothermic (ΔH°< 0). (D) Diamond has a density greater than that of graphite. (E) Diamond has a heat capacity lower than that of graphite. 121. _____________ At what temperature is G = 0 if So = 22.6 J K-1 and Ho = 15.3 kJ for a chemical reaction? (A) 404 oC (B) 677 oC (C) 0.67 oC (D) 1477 oC (E) 1204 oC 122. _____________ If ΔH° and ΔS° are both positive, then ΔG° is: (A) always positive (B) always negative (D) positive at low temperatures and negative at high temperatures (E) negative at low temperatures and positive at high temperatures (C) zero 123. _____________ CH4(g) + 2 O2(g) CO2(g) + 2 H2O(l); H = - 889.1 kJ Hf° H2O(l) = - 285.8 kJ / mole Hf° CO2(g) = - 393.3 kJ / mole What is the standard heat of formation of methane, Hf° CH4(g), as calculated from the data above? (A) -210.0 kJ/mole (B) -107.5 kJ/mole (C) -75.8 kJ/mole (D) 75.8 kJ/mole (E) 210.0 kJ/mole 124. _____________ H2(g) + ½ O2(g) H2O(l) ∆H° = x 2 Na(s) + ½ O2(g) Na2O(s) ∆H° = y Na(s) + ½ O2(g) + ½ H2(g) NaOH(s) ∆H° = z Based on the information above, what is the standard enthalpy change for the following reaction? Na2O(s) + H2O(l) 2 NaOH(s) (A) x + y + z (B) x + y – z (C) x + y - 2z (D) 2z - x – y (E) z - x – y 125. _____________ I2(g) + 3 Cl2(g) 2 ICl3(g) According to the data in the table below, what is the value of ∆H° for the reaction represented above? (A) - 870 kJ (B) - 390 kJ (C) + 180 kJ (D) + 450 kJ (E) + 1,260 kJ 126. _____________The cooling curve to the right shows how the temperature of a sample varies with time as the sample goes through phase changes. The sample starts as a gas and heat is removed at a constant rate. At which time does the sample contain the most liquid? (A) t1 (B) t2 (C) t3 (D) t4 (E) t5 Bond Average Bond Energy (kJ/mole) I---I 150 Cl---Cl 240 I---Cl 210 Questions 127-129 refer to the following combinations of enthalpy changes (∆H) and entropy changes (∆S) for chemical reactions. ∆H > 0, ∆S > 0 (B) ∆H > 0, ∆S < 0 (C) ∆H < 0, ∆S > 0 (D) ∆H < 0, ∆S < 0 (E) ∆H = 0, ∆S < 0 127. _____________ Must be true for a reaction that is spontaneous at all temperatures. 128. _____________ True for the evaporation of water at 25°C 129. _____________True for the combustion of liquid pentane, C5H12(l), to form H2O(g) and CO2(g) 130.____________ 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? (A) 14.6 (B) 46.0 (C) 88.0 (D) 94.1 (E) 138 131.____________A compound is heated to produce a gas whose molecular weight is to be determine(D) The gas is collected by displacing water in a water-filled flask inverted in a trough of water. Which of the following is necessary to calculate the molecular weight of the gas, but does NOT need to be measured during the experiment? (A) Mass of the compound used in the experiment (B) Temperature of the water in the trough (C) Vapor pressure of the water (D) Barometric pressure (E) Volume of water displaced from the flask 132.____________Which of the following is true at the triple point of a pure substance? (A) The vapor pressure of the solid phase always equals the vapor pressure of the liquid phase. (B) The temperature is always 0.01 K lower that the normal melting point. (C) The liquid and gas phases of the substance always have the same density and are therefore indistinguishable. (D) The solid phase always melts if the pressure increases at constant temperature. (E) The liquid phase always vaporizes if the pressure increases at constant temperature. 133.____________A 2.00-liter sample of nitrogen gas at 27 °C and 600. millimeters of mercury is heated until it occupies a volume of 5.00 liters. If the pressure remains unchanged, the final temperature (in Celsius) of the gas is (A) 68 °C (B) 120 °C (C) 477 °C (D) 677 °C (E) 950. °C 134.____________A hydrocarbon gas with an empirical formula CH2 has a density of 1.88 grams per liter at 0 °C and 1.00 atmospheres. A possible formula for the hydrocarbon is (A) CH2 (B) C2H4 (C) C3H6 (D) C4H8 (E) C5H10 135.____________A hot-air balloon rises. Which of the following is the best explanation for this observation? (A) The pressure on the walls of the balloon increases with increasing temperature. (B) The difference in temperature between the air inside and outside the balloon produces convection currents. (C) The cooler air outside the balloon pushes in on the walls of the balloon. (D) The rate of diffusion of cooler air is less than that of warmer air. (E) The air density inside the balloon is less than that of the surrounding air. 136.____________On a mountaintop, it is observed that water boils at 90°C, not at 100°C as at sea level. This phenomenon occurs because on the mountaintop the (A) equilibrium water vapor pressure is higher due to the higher atmospheric pressure (B) equilibrium water vapor pressure is lower due to the higher atmospheric pressure (C) equilibrium water vapor pressure equals the atmospheric pressure at a lower temperature (D) water molecules have a higher average kinetic energy due to the lower atmospheric pressure (E) water contains a greater concentration of dissolved gases 137.____________Which of the following gases deviates most from ideal behavior? (A) SO2 (B) Ne (C) CH4 (D) N2 (E) H2 138.____________ NH4NO3(s) N2O(g) + 2 H2O(g) A 0.03 mol sample of NH4NO3(s) is placed in a 1 L evacuated flask, which is then sealed and heate(D) NH4NO3 decomposes completely according to the balanced equation above. The total pressure in the flask measured at 400 K is closest to which of the following? (A) 3 atm (B) 1 atm (C) 0.5 atm (D) 0.1 atm (E) 0.03 atm 139.____________ Under which conditions will a gas behave most ideally? (A) high P and low T (B) low P and low T (C) low P and high T (D) high P and high T (E) a gas will behave ideally at all conditions 140.____________Equal masses of He and Ne are placed in a sealed container. What is the partial pressure of He if the total pressure in the container is 6 atm? (A) 1 atm (B) 2 atm (C) 3 atm (D) 4 atm (E) 5 atm 141.____________At standard temperature and pressure, a 0.50 mol sample of H2 gas and a separate 1.0 mol sample of O2 gas have the same: (A) average molecular kinetic energy (B) average molecular speed (C) volume (D) effusion rate (E) density Gas Amount Ar 0.35 mol 142.____________Three gases in the amounts shown in the table to the right are added to a CH4 0.90 mol previously evacuated rigid tank. If the total pressure in the tank is 3.0 atm at 25°C, the N2 0.25 mol partial pressure of N2(g) in the tank is closest to: (A) 0.75 atm (B) 0.50 atm (C) 0.33 atm (D) 0.25 atm (E) 0.17 atm 143.____________ When a sample of oxygen gas in a closed container of constant volume is heated until its Celsius temperature is doubled, which of the following is also doubled? (A) The density of the gas (B) The potential energy of the molecules (C) The pressure of the gas (D) The average velocity of the gas molecules (E) None of the above 144.____________ At 25°C, C2H6 effuses at a rate of 0.55 mol/minute. Which gas would have a rate of effusion approximately one-half as fast? (A) He (B) CH4 (C) NO (D) N2O3 (E) Cl2O3 145.____________An ideal gas in a rigid sealed container is heated from 330 K to 430 K. Which of the following DO NOT change? I. The density of the gas II. The average distance between molecules III. The average speed of the molecules (A) I only (B) III only (C) I & II only (D) I & III only (E) I, II, & III 146.____________A sample of gas in a closed container has its initial pressure doubled and its temperature held constant. Which of the following is true? (A) The volume of the gas doubles (B) The density of the gas doubles (C) The density of the gas halves (D) The size of the molecules doubles (E) The average kinetic energy of the molecules doubles 147.____________What is the total pressure after 2.00 moles of H2(g), 1.00 mole of O2(g), 2.00 moles of N2(g) and 1.00 mole CO2(g) are injected into a rigid 22.4 L container 273 K? (A) 760 mmHg (B) 2280 mmHg (C) 4560 mmHg (D) 9120 mmHg (E) 63,500 mmHg 148.____________ C3H7OH(s) H2O(g) + C3H6(g) A chemist places 0.10 moles of C3H7OH(s) in a 2.0 L flask. The flask is heated and C3H7OH(s) decomposes completely according to the equation above. The flask’s temperature is 500. K; calculate the approximate total pressure in the flask. (A) 8.0 atm (B) 50. atm (C) 25 atm (D) 2.0 atm (E) 4.0 atm 149.____________ S(s) + 3 F2(g) SF6(g) For the reaction above at standard temperature and pressure, the volume of F2 required to produce 0.500 mole of SF6 is: (A) 67.2 liters (B) 33.6 liters (C) 22.4 liters (D) 11.2 liters (E) 1.5 liters 150.____________A sample of 1.00 mole of hydrogen gas is mixed with 5.00 mole of helium gas. If the total pressure of the system is 3.00 atmospheres, the partial pressure of the helium gas is: (A) 0.500 atm (B) 1.00 atm (C) 1.50 atm (D) 2.00 atm (E) 2.50 atm 151.____________Collisions between gas particles and container walls result in a measurable pressure. Pressure varies: I. Directly with Kelvin temperature II. Inversely with the volume of the container III. Directly with the concentration of gas particles. (A) I only (B) II only (C) I and II only (D) I, II, and III (E) I and III only 152.______________ A 5.00 M solution with a volume of 400. mL is left uncovered and 75.0 mL evaporates. What is the new molarity of the solution? (A) 6.15 M (B) 26.7 M (C) 4.21 M (D) 5.00 M (E) 5.33 153.______________ A 580. mL solution contains 120. mL of ethanol (C2H5OH). Calculate the volume percent of this solution. (A) 20.7% (B) 4.83% (C) 7.47% (D) 4.50% (E) 0.207% 154. ______________ An aqueous solution is prepared to be 48.0% ethanol (C2H5OH) by volume. The density of ethanol is 0.789 g/mL. The density of the solution is 0.976 g/mL. Determine the mole fraction of ethanol in solution. (A) 0.636 (B) 0.389 (C) 0.611 (D) 0.480 (E) 0.201 155.______________ How many mL of stock sodium chloride solution would you need to prepare 700. mL of a 0.60 M solution from a 7.0 M stock solution? (A) 60. mL (B) 8200 mL (C) 640 mL (D) 120 mL (E) 30. mL 156.______________ Given that a solution is 20 percent sucrose by mass, what additional information is necessary to calculate the molarity of the solution? I. The density of water II. The density of the solution III. The molar mass of sucrose (A) I only (B) II only (C) III only (D) I and III (E) II and III 157.______________ A solution of 2.250 grams of an unknown molecular compound in 18.12 grams of camphor freezes at a temperature 12.2 Celsius degrees below the normal freezing point of pure camphor. Determine the molar mass of the unknown substance. Kf, for camphor is 40.0 kg-K-mol-1 (A) 407 g/mol (B) 204 g/mol (C) 102 g/mol (D) 305 g/mol (E) 30.5 g/mol 158.______________ How many kilograms of water are needed to make a 1.5 molal solution using 70.0 grams of CaCl2? (A) 0.95 kg (B) 0.42 kg (C) 2.4 kg (D) 47 kg (E) 0.047 kg 159.______________ I. Difference in temperature between freezing point of solvent and freezing point of solution II. Molal freezing point depression constant, Kf, for solvent In addition to the information above, which of the following gives the minimum data required to determine the molecular mass of a nonionic substance by the freezing point depression technique? (A) No further information is necessary. (B) Mass of solute (C) Mass of solute and mass of solvent (D) Mass of solute and volume of solvent (E) Mass of solute, mass of solvent, and vapor pressure of solvent 160.______________ Which of the following solutions has the lowest boiling point? (A) 0.20 m C6H12O6, glucose (B) 0.20 m NH4Br (C) 0.20 m ZnSO4 (D) 0.20 m KMnO4 (E) 0.20 m MgCl2 161.______________ A solution of toluene(C7H8) and benzene(C6H6) is prepare(D) If the mole fraction of toluene is 0.25, what is the mole fraction of benzene? (A) 25 (B) 0.25 (C) 0.75 (D) 0.29 (E) 0.71 162.______________ If the temperature of an aqueous solution of NaCl is increased from 20 °C to 90 °C, which of the following statements is true? (A) The density of the solution remains unchange(D) (B) The molality of the solution remains unchange(D) (C) The molarity of the solution remains unchange(D) (D) The mole fraction of solute decreases. (E) The mole fraction of solute increases. 163.______________ What is the percent mass of a solution that has 73.0 grams of NaCl dissolved in 275 grams of solution? (A) 0.265 % (B) 26.5% (C) 0.476% (D) 7.55% (E) 4.57% 164.______________ How many mL of water should be added to 200. mL of stock solution with a molarity of 5.00 to make a 1.50 M solution? (A) 667 mL (B) 867 mL (C) 60. mL (D) 140. mL (E) 467 mL 165.______________ An aqueous 1.0 m CaCl2 solution has a density of 1.05. Determine the molarity of the solution. (A) 2.84 M (B) 8.57M (C) 0.857 M (D) 10.0 M (E) 0.945 M 166.______________ How many liters of solution is produced in making a 4.1 M solution and using 190 grams of C12H22O11. (A) 0.14 L (B) 46 L (C) 2.3 L (D) 7.4 L (E) 0.046 L 167.______________ A solution is prepared by mixing 23.0 g ethanol (C2H5OH) with 100.0 g water to give a final volume of 119 mL. Calculate the molarity of ethanol in this solution. (A) 2.03 M (B) 8.90 M (C) 4.06 M (D) 1.93 M (E) 4.20 M 168.______________ If 345 grams of AlCl3 is dissolved in 890. grams of water, what is the mole fraction of aluminum chloride in water? (A) 0.388 (B) 38.8 (C) 0.0522 (D) 2.90 (E) 0.0496 169.______________ A student wishes to prepare 2.00 liters of 0.100-molar KIO3. The proper procedure is to weigh out (A) 42.8 grams of KIO3 and add 2.00 kilograms of H2O (B) 42.8 grams of KIO3 and add H2O until the final homogeneous solution has a volume of 2.00 liters (C) 21.4 grams of KIO3 and add H2O until the final homogeneous solution has a volume of 2.00 liters (D) 42.8 grams of KIO3 and add 2.00 liters of H2O (E) 21.4 grams of KIO3 and add 2.00 liters of H2O 170.______________ Calculate the molality of a 20.0 percent by weight aqueous solution of NaNO3. (A) 0.250 m (B) 0.235 m (C) 5.88 m (D) 2.94 m (E) 0.0502 m 171.______________ How many grams of sucrose, C12H22O11, would you need to make 0.50 kilogram of a 7.0% solution? (A) 12 g (B) 0.35 g (C) 0.070 g (D) 7.2 g (E) 35 g 172. _____________Which of the following statements is correct? (A) HClO2 is a stronger acid than HClO3 (B) HI is a weaker acid than HCl (C) H3PO4 is a stronger acid than HClO4 (D) HNO3 is a stronger acid than HNO2 (E) CH3COOH is a stronger acid than CH2BrCOOH 173. _____________ The only acid that is both a strong acid and a weak acid on dissociation is: (A) sulfuric acid (B) perchloric acid (C) nitric acid (D) hydrochloric acid (E) phosphoric acid 174. _____________ The Ka 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 11.0 175. _____________ Magnesium fluoride has a Ksp = 6.6 x 10-9. Which equation should be used to calculate the solubility of MgF2? (A) Ksp = x3 (B) Ksp = 2x3 (C) Ksp = 4x2 (D) Ksp = 27x3 (E) Ksp = 4x3 176. _____________ Which compound is an Arrhenius acid? (A) H2SO4 (B) KCl (C) NaOH (D) NH3 (E) CH4 177. _____________ The value of the acid-dissociation constant, Ka, for a weak monoprotic acid HA is 2.5 × 10−6. The pH of 0.40 M HA is closest to: (A) 2.0 (B) 3.0 (C) 4.0 (D) 6.0 (E) 8.0 178. _____________In an aqueous solution with a pH of 11.50 at 25°C, the molar concentration of OH−(aq) is approximately (A) 3.2 × 10−12 M (B) 3.2 × 10−3 M (C) 2.5 × 10−1 M 11 (D) 2.5 M (E) 3.2 × 10 M F−(aq) + H2O(l)qeHF(aq) + OH−(aq) 179. _____________Which of the following species, if any, acts as a Brønsted-Lowry base in the reversible reaction represented above? (C) F−(aq) only (A) HF(aq) (B) H2O(l) − − (D) Both F (aq) and OH (aq) act as Brønsted-Lowry bases. (E) No species acts as a Brønsted-Lowry base. 180. _____________By mixing only 0.15 M HCl and 0.25 M HCl, it is possible to create all of the following solutions EXCEPT: (A) 0.23 M HCl (B) 0.21 M HCl (C) 0.18 M HCl (D) 0.16 M HCl (E) 0.14 M HCl 181. _____________ Which ion is the only negative ion produced by an Arrhenius base in water? (A) NO3– (B) Cl– (C) OH– (D) H– (E) S2182. _____________At 25°C a saturated solution of a metal hydroxide, M(OH)2 , has a pH of 9.0. What is the value of the solubility-product constant, Ksp, of M(OH)2(s) at 25°C? (A) 5.0 × 10−28 (B) 1.0 × 10−27 (C) 5.0 × 10−19 (D) 5.0 × 10−16 (E) 1.0 × 10−15 183. _____________Which of the following is a weak acid in aqueous solution? (A) HCl (B) HClO4 (C) HNO3 (D) H2S (E) H2SO4 NH3(aq) + HCl(aq) qe NH4+(aq) + Cl-(aq) 184. _____________ The Brønsted-Lowry bases in the reaction represented above are: (A) NH3(aq) and NH4+(aq) (B) NH3(aq) and Cl-(aq) (C) NH3(aq) and HCl(aq) + (D) HCl(aq) and NH4 (aq) (E) HCl(aq) and Cl-(aq) 185. _____________ The value of Ksp for PbCl2 is 1.6 x 10-5. What is the lowest concentration of Cl−(aq) that would be needed to begin precipitation of PbCl2(s) in 0.010 M Pb(NO3)2? (A) 1.6 x 10-7 M (B) 4.0 x 10-4 M (C) 1.6 x 10-3 M (D) 2.6 x 10-3 M (E) 4.0 x10-2 M For questions 186-190 consider the following system at equilibrium: 2N2O(g) qe2N2(g) + O2(g) ∆H = +163 kJ and select from the following choices: (A) to the right (B) to the left (C) neither (D) in both directions (E) cannot be determined from information provided 186. _____________ In which direction will the system move in order to reestablish equilibrium if the temperature is raised? 187. _____________ In which direction will the system move in order to reestablish equilibrium if the volume is increased? 188. _____________ In which direction will the system move in order to reestablish equilibrium if O2 is added? 189. _____________ In which direction will the system move in order to reestablish equilibrium if a catalyst is added? 189. _____________ In which direction will the system move in order to reestablish equilibrium if N2O is removed? 190. _____________ In which direction will the system move in order to reestablish equilibrium if a sample of Kr is added? 191. ____________ Which of the following will occur when a solution of a weak acid is diluted? I. The pH of the solution will increase II. The equilibrium constant for the acid will decrease III. The dissociation of the acid will increase (A) I only (B) III only (C) I, II, and III (D) II and III only (E) I and III only 192. ____________ How many moles of NaF must be dissolved in 1.00 liter of a saturated solution of PbF2 at 25°C to reduce the [Pb2+] to 1 x 10-6 molar? (Ksp of PbF2 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 193. ____________ Which of the following best describes the pH of a 0.01 molar solution of C5H5N5 (Kb = 1.7 x 10-9)? (A) Less than or equal to 2.0 (B) Between 2 and 7 (C) 7 (D) Between 7 and 11 (E) Greater than or equal to 11 194. ____________HSO4- + H2O qe H3O+ + SO42In the equilibrium represented above, the species that act as bases include which of the following? II. HSO4III. SO42I. H2O (A) II only (B) III only (C) I and II (D) I and III (E) II and III 195. ____________ Which of the following is not a conjugate acid-base pair? (A) H2SO4 and HSO4(B) HCl and Cl(C) NH3 and NH23(D) H2PO4 and PO4 (E) H2S and HS 196. ____________ What is the H+ (aq) concentration in 0.05 M HCN (aq)? (The Ka for HCN is 5.0 x 10-10) (A) 2.5 x 10-11 (B) 2.5 x 10-10 (C) 5.0 x 10-10 (D) 5.0 x 10-6 (E) 5.0 x 10-4 197. ____________ A 0.20-molar solution of a weak monoprotic acid, HA, has a pH of 3.00. The ionization constant(Ka) of this acid is: (A) 5.0 x 10-7 (B) 2.0 x 10-7 (C) 5.0 x 10-6 (D) 5.0 x 10-3 (E) 2.0 x 10-3 198. ____________ 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 199. ____________ 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 200. ____________ Which of the following can function as both a Brønsted-Lowry acid and Brønsted-Lowry base? (A) HCl (B) H2SO4 (C) HSO3(D) SO42(E) H+ 201. ____________ The solubility product, Ksp, of CaF2 is 4 x 10-11. Which of the following expressions is equal to the solubility of CaF2? (A) 4 x1011 M (B) (D) 3 2 x1011 M 2 x1011 M (C) (E) 3 1x1011 M 3 4 x1011 M 202. ____________ How many moles of calcium fluoride, CaF2, must be dissolved in 2.0 L of water at 25°C to form a saturated solution? CaF2 1.6 x l0–10 Ksp at 25 °C (A) 2.6 x l0–2 mol (B) 1.3 x l0–3 mol (C) 6.8 x l0–4 mol –4 –10 (D) 3.4 x l0 mol (E) 1.6 x l0 mol 203. ____________ The ionization of benzoic acid is represented by this equation. C6H5COOH(aq) qe H+(aq) + C6H5COO–(aq) If a 0.045 M solution of benzoic acid has an [H+] = 1.7 x l0–3, what is the Ka of benzoic acid? (A) 7.7 x l0–5 (B) 6.7 x l0–5 (C) 3.8 x l0–2 –1 –6 (D) 8.4 x l0 (E) 2.9 x l0 204. ____________ C6H5OH(aq) + CN–(aq)qe HCN(aq) + C6H5O–(aq) The equilibrium constant for this reaction is less than 1. What is the strongest base in this system? (A) C6H5OH(aq) (B) CN–(aq) (C) HCN(aq) – (D) C6H5O (aq) (E) all bases are equal in strength 205. ____________What is the conjugate base of H2PO4–? (A) HPO42–(aq) (B) H2O(l) (D) H3PO4(aq) (E) HPO4 (C) HPO4–(aq) 206.______________ Which of the following solutions has the lowest boiling point? (A) 0.20 m C6H12O6, glucose (B) 0.20 m NH4Br (C) 0.20 m ZnSO4 (D) 0.20 m KMnO4 (E) 0.20 m MgCl2 207.______________ How many mL of water should be added to 200. mL of stock solution with a molarity of 5.00 to make a 1.50 M solution? (A) 667 mL (B) 867 mL (C) 60. mL (D) 140. mL (E) 467 mL 208.______________ Calculate the molality of a solution that contains 6.5 moles of sodium chloride dissolved in 725 grams of water. (A) 0.0090 m (B) 0.16 m (C) 9.0 m (D) 110 m (E) 4.7 m 209.______________ How many mL of acetic acid, HC2H3O2, is needed to make 1.0 L of a 15.0% acetic acid solution? (A) 150 mL (B) 15 mL (C) 870 mL (D) 6.7 mL (E) 1500 mL 210.______________ Calculate the molality of a 20.0 percent by weight aqueous solution of NaNO3. (A) 0.250 m (B) 0.235 m (C) 5.88 m (D) 2.94 m (E) 0.0502 m 211.______________ How many grams of sucrose, C12H22O11, would you need to make 0.50 kilogram of a 7.0% solution? (A) 12 g (B) 0.35 g (C) 0.070 g (D) 7.2 g (E) 35 g 212.______________ A solution of 2.250 grams of an unknown molecular compound in 18.12 grams of camphor freezes at a temperature 12.2 Celsius degrees below the normal freezing point of pure camphor. Determine the molar mass of the unknown substance. Kf, for camphor is 40.0 kg-K-mol-1 (A) 407 g/mol (B) 204 g/mol (C) 102 g/mol (D) 305 g/mol (E) 30.5 g/mol 213.______________ What is the percent mass of a solution that has 73.0 grams of NaCl dissolved in 275 grams of solution? (A) 0.265 % (B) 26.5% (C) 0.476% (D) 7.55% (E) 4.57% 214.______________ How many kilograms of water are needed to make a 1.5 molal solution using 70.0 grams of CaCl2? (A) 0.95 kg (B) 0.42 kg (C) 2.4 kg (D) 47 kg (E) 0.047 kg 215.______________ A solution of toluene(C7H8) and benzene(C6H6) is prepare(D) If the mole fraction of toluene is 0.25, what is the mole fraction of benzene? (A) 25 (B) 0.25 (C) 0.75 (D) 0.29 (E) 0.71 216.______________ A 5.00 M solution with a volume of 400. mL is left uncovered and 75.0 mL evaporates. What is the new molarity of the solution? (A) 6.15 M (B) 26.7 M (C) 4.21 M (D) 5.00 M (E) 5.33 217.______________ Given that a solution is 20 percent sucrose by mass, what additional information is necessary to calculate the molarity of the solution? I. The density of water II. The density of the solution III. The molar mass of sucrose (A) I only (B) II only (C) III only (D) I and III (E) II and III 218.______________ If the temperature of an aqueous solution of NaCl is increased from 20 °C to 90 °C, which of the following statements is true? (A) The density of the solution remains unchange(D) (B) The molality of the solution remains unchange(D) (C) The molarity of the solution remains unchange(D) (D) The mole fraction of solute decreases. (E) The mole fraction of solute increases. 219.______________ Determine the boiling point if 600. grams of toluene (C7H8) is dissolved in 800. grams of benzene(C6H6). Boiling Point of benzene: 80.10ºC, Kb = 2.53 kg-K-mol-1 (A) 100.7°C (B) 59.5°C (C) 20.6°C (D) 82.00°C (E) 1.90°C 220.______________ An aqueous 1.0 m CaCl2 solution has a density of 1.05. Determine the molarity of the solution. (A) 2.84 M (B) 8.57M (C) 0.857 M (D) 10.0 M (E) 0.945 M 221.______________ How many mL of stock sodium chloride solution would you need to prepare 700. mL of a 0.60 M solution from a 7.0 M stock solution? (A) 60. mL (B) 8200 mL (C) 640 mL (D) 120 mL (E) 30. mL 222.______________ A solution is prepared by mixing 23.0 g ethanol (C2H5OH) with 100.0 g water to give a final volume of 119 mL. Calculate the molarity of ethanol in this solution. (A) 2.03 M (B) 8.90 M (C) 4.06 M (D) 1.93 M (E) 4.20 M 223.______________ If 345 grams of AlCl3 is dissolved in 890. grams of water, what is the mole fraction of aluminum chloride in water? (A) 0.388 (B) 38.8 (C) 0.0522 (D) 2.90 (E) 0.0496 224______________ A 580. mL solution contains 120. mL of ethanol (C2H5OH). Calculate the volume percent of this solution. (A) 20.7% (B) 4.83% (C) 7.47% (D) 4.50% (E) 0.207% 225. ______________ An aqueous solution is prepared to be 48.0% ethanol(C2H5OH) by volume. The density of ethanol is 0.789 g/mL. The density of the solution is 0.976 g/mL. Determine the mole fraction of ethanol in solution. (A) 0.636 (B) 0.389 (C) 0.611 (D) 0.480 (E) 0.199 226.______________ How many liters of solution is produced in making a 4.1 M solution and using 190 grams of C12H22O11. (A) 0.14 L (B) 46 L (C) 2.3 L (D) 7.4 L (E) 0.046 L 227.______________ A student wishes to prepare 2.00 liters of 0.100-molar KIO3. The proper procedure is to weigh out (A) 42.8 grams of KIO3 and add 2.00 kilograms of H2O (B) 42.8 grams of KIO3 and add H2O until the final homogeneous solution has a volume of 2.00 liters (C) 21.4 grams of KIO3 and add H2O until the final homogeneous solution has a volume of 2.00 liters (D) 42.8 grams of KIO3 and add 2.00 liters of H2O (E) 21.4 grams of KIO3 and add 2.00 liters of H2O 228.______________ Calculate the mass of CaBr2 needed to make 870 mL of a 0.75 M solution. (A) 170 g (B) 11.6 g (C) 0.86 g (D) 0.65 g (E) 130 g 229.______________ Determine the freezing point if 4.0 moles of Na2SO4 is dissolved in 6.0 kilograms of water. Freezing point: 0.0ºC, Kf = 1.86 kg-K-mol-1 (A) 3.72°C (B) 1.24°C (C) -1.24°C (D) -2.48°C (E) -3.72°C 230.______________ I. Difference in temperature between freezing point of solvent and freezing point of solution II. Molal freezing point depression constant, Kf, for solvent In addition to the information above, which of the following gives the minimum data required to determine the molecular mass of a nonionic substance by the freezing point depression technique? (A) No further information is necessary. (B) Mass of solute (C) Mass of solute and mass of solvent (D) Mass of solute and volume of solvent (E) Mass of solute, mass of solvent, and vapor pressure of solvent 231. ____________ A sample of 5.16 grams of an ideal gas at 150.0 °C and 1.25 atmospheres pressure has a volume of 2.00 liters. What is the molar mass of the gas? (A) 0.0218 gram/mole (B) 16.2 grams/mole (C) 37.0 grams/mole (D) 45.8 grams/mole (E) 71.6 grams/mole 232.____________ A gas has a volume of 4.0 L at a pressure of 0.80 atm. What is the volume if the pressure is changed to 0.20 atm at constant temperature? (A) 1.0 L (B) 2.0 L (C) 8.0 L (D) 16 L (E) 6 L 233. ____________Equal numbers of moles of CO2(g), SO2(g), and H2O(g) are placed in a glass vessel at 400. K. If the vessel has a pinhole-sized leak, which of the following will be true regarding the relative values of the partial pressures of the gases remaining in the vessel after some of the gas mixture has effused? (A) PCO2 < PSO2 < PH2O (B) PCO2 < PH2O < PSO2 (C) PSO2 < PCO2 < PH2O (D) PH2O < PCO2 < PSO2 (E) PCO2 = PSO2 = PH2O 234.____________ A 0.239 g sample of a gas in a 100-mL flask exerts a pressure of 1520 mmHg at 14 °(C) What is the gas? (A) chlorine (B) nitrogen (C) krypton (D) xenon (E) oxygen 235.____________ A sample of neon gas has a volume of 333 mL at 30.°C and a certain pressure. What volume would it occupy if it were heated to 60.°C at the same pressure? (A) 366 mL (B) 399 mL (C) 333 mL (D) 666 mL (E) 167 mL 236. ____________ Hydrogen gas is collected over water at 21°(C) At 21°C the vapor pressure of water is 18.7 torr. If the barometric pressure is 758 torr what is the pressure of hydrogen gas? (A) 758 torr (B) 777 torr (C) 739 torr (D) 48.2 torr (E) 18.7 torr 237. ____________ Calculate the root mean square velocity of a sample of 10.0 grams of helium atoms at 55.0 °(C) (A) 45.2 m/s (B) 142 m/s (C) 1010 m/s (D) 1110 m/s (E) 1430 m/s 238. ____________ When a sample of oxygen gas in a closed container of constant volume is heated until its Celsius temperature is doubled, which of the following is also doubled? (A) The density of the gas (B) The potential energy of the molecules (C) The pressure of the gas (D) The average velocity of the gas molecules (E) None of the above 239.____________Helium is often found with methane, CH4. How do the diffusion rates of helium and methane compare at the same temperature? Methane diffuses: (A) ½ as fast as helium. (B) four times as fast as helium. (C) twice as fast as helium. (D) at the same rate as helium. (E) ¼ as fast as helium. 240.____________ Under which conditions will a gas behave most ideally? (A) high P and low T (B) low P and low T (C) low P and high T (D) high P and high T (E) a gas will behave ideally at all conditions 241. ____________ Xenon gas initially at 35ºC is heated to 105ºC in a closed container. Which statement is correct? (A) The average kinetic energy of the xenon atoms does not change. (B) The average kinetic energy of the xenon atoms triples. (C) The pressure of the gas increases by 23 percent. (D) The pressure of the gas triples. (E) The pressure of the gas increases by about 8 percent. 242.____________Which gas has a density of 2.58 g·L–1 at 10.°C and 1.5 atm? (A) Ar (B) Ne (C) CO (D) CH4 (E) Kr 243.____________ A gas mixture at 27°C and 760 mm Hg contains 1.0 g each of He, O2, N2 and CO. How do their average molecular speeds compare? (A) He = O2 = N2 = CO (B) O2 < N2 = CO < He (C) He < CO = N2 < O2 (D) CO < O2 < N2 < He (E) He < O2 < CO < N2 244. ____________ Which of the following would express the approximate density of sulfur dioxide gas at 0°C and 3.00 atm pressure (in grams per liter)? (A) 2.2 g/L (B) 4.3 g/L (C) 6.5 g/L (D) 8.6 g/L (E) 5.5 g/L 245. ____________ 2Li(s) + 2HCl (aq) H2(g) + 2LiCl(aq) Calculate the volume of Hydrogen produced if 3.55 grams of Li react with excess HCl if the pressure is 0.98 atm and the temperature is 29.0 °C. (A) 6.50 L (B) 13.0 L (C) 3.25 L (D) 44.9 L (E) 89.8 L 246. ____________ Three balloons are each filled to a volume of 40.0 L with Ar, Kr, and Xe, respectively. Which statement is true under the same conditions of temperature and pressure? (A) The balloons contain the same mass of gas. (B) All gases have the same kinetic energy. (C) The densities of the three gases are the same. (D) The gases will all effuse at the same rate. (E) All gases have the same root mean square velocity. Questions 247–249 refer to the following gases at 0˚C and 1 atm. (A) Ne (B) Xe (C) O2 (D) CO (E) NO 247. ____________ Has an average atomic or molecular speed closest to that of N2 molecules at 0˚C and 1 atm. 248. ____________ Has the greatest density. 249. ____________ Has the greatest rate of effusion through a pinhole. Questions 250–252 The phase diagram for the pure substance X is shown to the right. 250. ____________ The temperature of a sample of pure solid X is slowly raised from 10˚C to 100˚C at a constant pressure of 0.5 atm. What is the expected behavior of the substance? (A) It first melts to a liquid and then boils at about 70˚(C) (B) It first melts to a liquid and then boils at about 30˚(C) (C) It melts to a liquid at a temperature of about 20˚C and remains a liquid until the temperature is greater than 100˚(C) (D) It sublimes to vapor at an equilibrium temperature of about 20˚ (C) (E) It remains a solid until the temperature is greater than 100˚(C) 251. ____________ What is the approximate normal boiling point for a pure sample of substance X? (A) 28 °C (B) 37 °C (D) 60 °C (D) 70°C (E) 102 °C 252. ____________ Which state of matter of substance X is the most dense? (A) all states are equally dense (B) it is impossible to determine without more information (C) solid X (D) liquid X (E) gas X 253. ____________ Substance C6H6(l) C2H5OH(l) CH3OH(l) C4H9OH(l) C2H6O2(l) Equilibrium Vapor Pressure at 20°C (torr) 75 44 92 32 0.06 Based on the data in the table above, which of the following liquid substances has the weakest intermolecular forces? (A) C6H6(l) (B) C2H5OH(l) (C) CH3OH(l) (D) C4H9OH(l) (E) C2H6O2(l) 254. ____________ Shown to the right is the phase diagram of a pure substance. The substance under the conditions corresponding to point X on the diagram is cooled to 40°C while the pressure remains constant. As the substance cools, the phase of the substance changes from (A) gas to liquid to solid (B) gas to solid to liquid (C) solid to liquid to gas (D) liquid to solid to gas (E) liquid to gas to solid 255.____________ At which temperature and pressure is substance X a liquid? (A) 1.0 atm, 20°C only (B) 1.5 atm, 40°C only (C) 0.5 atm, 60°C only (D) two of the above are true (E) none of the above are true. 256. ____________ A flask contains 0.25 mole of SO2(g), 0.50 mole of CH4(g), and 0.50 mole of O2(g). The total pressure of the gases in the flask is 800 mm Hg. What is the partial pressure of the SO2(g) in the flask? (A) 800 mm Hg (B) 600 mm Hg (C) 250 mm Hg (D) 200 mm Hg (E) 160 mm Hg 257. ____________ A gas shows most ideal behavior at: (A) high temperatures and high pressure (B) high temperatures and low pressure (C) low temperatures and low pressure (D) low temperature and high pressure (E) all temperatures and pressures 258. ____________ A 2 L container will hold about 4 g of which of the following gases at 0˚C and 1 atm? (A) SO2 (B) N2 (C) CO2 (E) NH3 (D) C4H8 259. ____________ Which of the following gasses shows most ideal behavior at 25°C and 1 atm? (A) Ar (B) Cl2 (C) He (D) CH4 (E) O2 260. ____________ Three gases in the amounts shown in the table to the right are added to a previously evacuated rigid tank. If the total pressure in the tank is 3.0 atm at 25 C, the partial pressure of N2(g) in the tank is closest to: (A) 0.75 atm (B) 0.50 atm (C) 0.33 atm (D) 0.25 atm (E) 0.17 atm Gas Ar CH4 N2 Amount 0.35 mol 0.90 mol 0.25 mol 261. ____________ At approximately what temperature will 40. Grams of argon gas at 2.0 atm occupy avolume of 22.4 L? (A) 1,200 K (B) 600 K (C) 550 K (D) 270 K (E) 140 K 262. ____________ 8H2(g) + S8(s) 8H2S(g) When 25.6 g of S8(s) reacts completely with an excess of H2(g) according to the equation above, the volume of H2S(g), measured at 0°C and 1.00 atm, produced is closest to: (A) 30 L (B) 20 L (C) 10 L (D) 5 L (E) 2 L 263. ____________ At which of the following temperatures and pressures would a real gas be most likely to deviate from ideal behavior? (A) (B) (C) (D) (E) Temperature (K) 100 200 300 500 500 Pressure (atm) 50 5 0.01 0.01 1 264. ____________ Of the following gases, which has the greatest average molecular speed at 298 K? (A) Cl2(g) (B) NO(g) (C) H2S(g) (D) HCN(g) (E) PH3(g) 265. ____________ Which liquid is most volatile at 25°C? (A) butane, C4H10 (B) glycerol, C3H5(OH)3 (D) propanol, C3H7OH (E) nonane, C10H22 266._______________ For which of these is ΔHf° not equal to zero? (A) Br2(l) (B) Fe(s) (C) I2(s) (C) octane, C8H18 (D) O3(g) 267. _______________ The enthalpy change for which reaction represents the standard enthalpy of formation for hydrogen cyanide, HCN? (A) H(g) + C(graphite) + N(g) →HCN(g) (B) ½H2(g) + C(graphite) + ½ N2(g) → HCN(g) (D) H2(g) + 2C(graphite) + N2(g) →2HCN(g) (C) HCN(g) → ½ H2(g) + C(graphite) + ½ N2(g) 268. _______________ What is the standard enthalpy of formation of MgO(s) if 300.9 kJ is evolved when 20.15 g of MgO(s) is formed by the combustion of magnesium under standard conditions? (A) –601.8 kJ·mol–1 (B) –300.9 kJ·mol–1 (C) +300.9 kJ·mol–1 (D) +601.8 kJ·mol–1 269. _______________ Which change occurs with the largest increase in entropy at 25˚C? (A) Br2(l) → Br2(g) (B) C(graphite) → C(diamond) (C) H2O(s) → H2O(l) (D) HCl(g) + H2O(l) → H3O+(aq) + Cl–(aq) 270. _______________ What are the signs of ΔH˚ and ΔS˚ for a reaction that is spontaneous at all temperatures? ΔH˚ ΔS˚ (A) + + (B) + – (C) – + (D) – – 271. _______________ For the formation of one mole of each of these gases from their elements, which reaction is most endothermic? (A) CO (ΔHf° = –110.5 kJ·mol–1) (B) NO2 (ΔHf° = +33.9 kJ·mol–1) –1 (D) SO2 (ΔHf° = –300.4 kJ·mol–1) (C) O3 (ΔHf° = +142.2 kJ·mol ) 272. _______________ 4Li(s) + O2(g) 2Li2O(s) At 25°C, ΔH° for this reaction is –598.8 kilojoules per mole of Li2O(s) forme(D) What mass of Li should be reacted with excess O2(g) in order to release 150. kJ? (A) 0.874 g (B) 1.74 g (C) 3.48 g (D) 6.98 g 273. _______________ When these substances are arranged in order of increasing S° values at 25 °C, what is the correct order? (A) Na(s), Cl2(g), NaCl(s) (B) NaCl(s), Cl2(g), Na(s) (C) Cl2 (g), NaCl(s), Na(s) (D) Na(s), NaCl(s), Cl2(g) 274. _______________ The ΔH° and ΔS° values for a particular reaction are –60.0 kJ and –0.200 kJ·K–1 respectively. Under what conditions is this reaction spontaneous? (A) all conditions (B) T < 300 K (C) T = 300 K (D) T > 300 K 275. _______________ Which reaction occurs with an increase in entropy? (A) 2C(s) + O2(g) 2CO(g) (B) 2H2S(g) + SO2(g) 3S(s) + 2H2O(g) (C) 4Fe(s) + 3O2(g) 2Fe2O3(s) (D) CO(g) + 2H2(g) CH3OH(l) 276. _______________ Consider this reaction. 2N2H4(l) + N2O4(l) 3N2(g) + 4H2O(g) ΔH = –1078 kJ How much energy is released by this reaction during the formation of 140. g of N2(g)? (A) 1078 kJ (B) 1797 kJ (C) 3234 kJ (D) 5390 kJ 277. _______________ For the reaction PCl3(g) + Cl2(g) PCl5(g), ΔH° = –86 kJ. Under what temperatures is this reaction expected to be spontaneous? (A) no temperatures (B) high temperatures only (C) all temperatures (D) low temperatures only 278. _______________ Use the information in the table to calculate the enthalpy of this reaction. C2H6(g) + 7/2 O2(g) 2CO2(g) + 3H2O(l) Reaction ΔHf° , kJ·mol–1 2C(s) + 3H2(g) C2H6(g) –84.7 C(s) + O2(g) CO2(g) –393.5 H2(g) + ½O2(g) H2O(l) –285.8 (A) –764 kJ (B) –1560 kJ (C) –1664 kJ (D) –3120 kJ 279. _______________ Given the thermochemical equations: Br2(l) + F2(g) 2BrF(g) ΔH° = -188 kJ Br2(l) + 3F2(g) 2BrF3(g) ΔH° = -768 kJ determine ΔH° for the reaction: BrF(g) + F2(g) BrF3(g) (A) -956 kJ (B) -580 kJ (C) -478 kJ ΔH° = ? 280. _______________ Use bond energies to calculate ΔH° for the reaction: H2(g) + O2(g) H2O2(g) Bond Bond Energy, kJ.mol-1 H-H 432 H-O 459 O-O 207 O=O 494 (A) -521 kJ (B) -486 kJ (C) -199 kJ (D) -290 kJ (D) 199 kJ 281. _______________ Which reaction occurs with a decrease in entropy? (A) N2(g) + O2(g) 2NO(g) (B) N2O4(g) 2NO2(g) (C) 2CO(g) C(s) + CO2(g) (D) 2HCl(aq) + Ag2CO3(s) 2AgCl(s) + CO2(g) + H2O(l) 282. _______________ The enthalpy change of which reaction corresponds to ΔHf°for Na2CO3(s) at 298 K? (A) 2Na(s) + C(s) + 3/2 O2(g) Na2CO3(s) (B) Na2O(s) + CO2(g) Na2CO3(s) (C) 2Na+(aq) + CO32-(aq) Na2CO3(s) (D) 2Na+(aq) + 2OH–(aq) + CO2(aq) Na2CO3(s) + H2O 283. _______________ Which applies to any endothermic reaction? (A) ΔH < 0 (B) ΔH > 0 (C) ΔG < 0 (D) ΔG > 0 284. _______________ Which reaction occurs with the greatest increase in entropy? (A) 2H2O(l) 2H2(g) + O2(g) (B) 2NO(g) N2(g) + O2(g) (C) C(s) + O2(g) CO2(g) (D) Br2(g) + Cl2(g) 2BrCl(g) 285. _______________ When a catalyst is added to the system represented by this energy-reaction coordinate diagram, which dimensions in the diagram are changed? (A) 1 and 2 only (B) 1 and 3 only (C) 2 and 3 only (D) 1, 2, 3 Use the following answers for problems 286-289. You may use an answer more than once. (A) ∆G (B) ∆S (C) Heat of vaporization (D) Heat of fusion (E) Specific heat 286. _____________ If it has a negative value for a process, then the process occurs spontaneously. 287. _____________ This is a measure of how the disorder or positional probability in a system is changing. 288. _____________ This is the energy given off when a substance condenses. 289._____________ This is the amount of energy need to raise the temperature of one gram of a substance one degree Celsius. 290. ____________ 2Al(s) + 3Cl2(g) 2AlCl3(s) The reaction above is not spontaneous at standard conditions, but becomes spontaneous as the temperature decreases towards absolute zero. Which of the following is true at standard conditions? (A) ∆S and ∆H are both negative (B) ∆S and ∆H are both positive (C) ∆S is negative and ∆H is positive (D) ∆S is positive and ∆H is negative (E) ∆S and ∆H are both equal to zero 291. _____________ 2H2(g) + O2(g) 2H2O(g) Based on the information in the table below, what is the ∆H for the above reaction? Bond Average Bond Energy (kJ/mol) H-H 432 O=O 495 O-H 467 (A) +460 kJ (B) +425 kJ (C) +509 kJ (D) -509 kJ (E) -460 kJ 292. _____________ Based on the information given below, what is the ∆H for the following reaction: C2H2(g) + 5/2 O2 2CO2(g) + H2O Reaction ∆H C(s) + O2(g) CO2(g) ∆H = -390 kJ/mol H2(g) + ½ O2(g) H2O(l) ∆H = -290 kJ/mol 2C(s) + H2(g) C2H2(g) ∆H = +230 kJ/mol (A) -1300 kJ (B) -1070 kJ (C) -840 kJ (D)-780 kJ (E) -680 kJ 293._____________ The addition of a catalyst will have which of the following effects on a chemical reaction? The enthalpy will decrease. The entropy will decrease. The activation energy will decrease. (A) I only (B) II only (C) III only (D) I and II only (E) II and III only 294. _____________ For which of the following processes will ∆S be positive? NaCl(s) Na+(aq) + Cl-(aq) 2H2(g) + O2(g) 2H2O(g) CaCO3(s) CaO(s) + CO2(g) (A) I only (B) II only (C) I and II only (D) I and III only (E) 1, II and III 295._____________ The energy diagram for the reaction X + Y Z is shown to the right. The addition of a catalyst to this reaction would cause a change in which of the indicated energy differences? (A) I only (B) II only (C) III only (D) I and II only (E) I, II, and III 296. ____________ 4Fe + 3O2 2Fe2O3 – How many liters of O2 are needed to create 1.00 gram of Fe2O3 at STP? (A) 0.211 L (B) 0.421 L (C) 22.4 L (D) 67.2 L e. none of the above 297. ____________ 4HCl + O2 2H2O + 2Cl2 – How many moles of H2O can be produced from 30. moles of HCl? (A) 15 moles (B) 30. moles (C) 45 moles (D) 60. moles e. none of the above 298. ____________ 2H2 + O2 2H2O – How many moles of water can be produced from 18.0 grams of H2 and excess O2? (A) 4.5 moles (B) 9.0 moles (C) 18.0 moles (D) 162 moles e. none of the above 299. ____________ 2Na + Cl2 2NaCl – How many grams of NaCl can be produced from 1.00 mole of sodium? (A) 2.50 grams (B) 29.3 grams (C) 58.5 grams (D) 117 grams e. none of the above 300. ____________ 4Al + 3O2 2Al2O3 – How many liters of O2 are needed to react with 162 grams of Al? (A) 67.2 L (B) 96.0 L (C) 269 L (D) 384 L e. none of the above 301. ____________ 2SO2 + O2 2SO3 – How many liters of SO3 can be produced from 5.00 liters of oxygen at STP? (A) 2.50 L (B) 5.00 L (C) 10.0 L (D) 20.0 L e. none of the above 302. ____________ C3H8 + 5O2 3CO2 + 4H2O – How many liters of CO2 are produced from burning 88.0 grams of C3H8 at STP? (A) 44.8 L (B) 67.2 L (C) 89.6 L (D) 134 L e. none of the above 303. ____________ Na2CO3 Na2O + CO2 – How many liters of CO2 at STP can be produced from 3.00 moles of Na2CO3? (A) 3.00 L (B) 22.4 L (C) 33.6 L (D) 67.2 L e. none of the above 304. ____________ Zn + 2HCl ZnCl2 + H2 – How many moles of HCl are needed to react with 65.4 moles of Zn (A) 2.00 moles (B) 22.4 moles (C) 44.8 moles (D) 131 moles e. none of the above 305. ____________ 2Al + 3FeO Al2O3 + 3Fe – A student uses 54.0 grams of aluminum and produces 150.4 grams of iron. What is his percent yield? (A) 10.2% (B) 35.9% (C) 89.8% (D) 98.7% e. none of the above 306. ____________ CH4 + 2O2 CO2 + 2H2O - Using 32.0 grams of methane Lisa was able to produce 63.0 grams of water. Calculate her percent yield? (A) 17.5% (B) 57.1% (C) 77.8% (D) 87.5% e. none of the above 307. ____________ 3H2 + N2 2NH3 - Given 28.1 grams of N2 and 30.0 liters of H2, which is your limiting reagent? (A) N2 (B) H2 (C) NH3 (D) both H2 & N2 e. can’t be determined 308. ____________ 2Al + 3S Al2S3 - Aluminum reacts with sulfur to produce aluminum sulfide. If I have 81 grams of Al and 81 grams of S, what is my limiting reagent? (A) S (B) Al (C) Al2S3 (D) both Al & S e. can’t be determined 309. ____________ 2KClO3 2KCl + 3O2 - Potassium chlorate decomposes to form potassium chloride and oxygen gas. How many liters of oxygen gas at STP are produced from 490.4 grams of potassium chlorate? (A) 59.7 L (B) 134 L (C) 192 L (D) 268 L e. none of the above 310. ____________ If the theoretical value is 4.75 grams and in the lab you measure 3.23 grams, what is the percent yield? (A) 1.52 % (B) 1.47 % (C) 68.0 % (D) 87.4 % e. none of the above 311. __________ Which of the following bonds is the weakest? (A) single covalent bond (B) double covalent bond (C) triple covalent bond (D) hydrogen bond 312. __________ Which of the following types of attractions is the strongest? (A) dispersion forces (B) dipole interactions (C) covalent bonds (D) hydrogen bonds 313. __________ Which of the following molecules has polar bonds but is a non-polar molecule? (A) silicon tetrahydride (B) ammonia (C) silicon dioxide (D) dihydrogen monoxide 314. __________ Which of the following is a non-polar covalent bond? (A) C - N (B) N - H (C) C - O (D) N - O 315. __________ Which of the following is an ionic bond? (A) H-O (B) P-F (C) C-O (D) O-K 316. __________ Which of the following intermolecular forces explains why fluorine is a gas, but iodine is a solid? (A) dispersion forces (B) dipole interactions (C) hydrogen bonds (D) covalent bonds 317. __________ Which of the following molecules would have the most hydrogen bonding? (A) H2O (B) H2 (C) CH4 (D) HCN 318. __________ Which of the following molecules has the strongest dispersion forces? (A) H2 (B) I2 (C) Br2 (D) F2 319. __________ Which of the following compounds does not have a resonance structure? (A) sulfur dichloride (B) nitrate ion (C) sulfur dioxide (D) carbonate ion 320. __________ Which of the following elements does not follow the octet rule? (A) carbon (B) nitrogen (C) hydrogen (D) iodine 321. __________ Which of the following bonds is the longest? (A) single bond (B) double bond (C) triple bond (D) all bonds are the same length 322. __________ Which of the following best describes the bond between chlorine and bromine in BrCl? (A) polar single covalent bond (B) non-polar single covalent bond (C) polar double covalent bond (D) non-polar covalent bond 323. __________ Which of the following molecules has the strongest bonds between atoms? (A) H2 (B) F2 (C) O2 (D) N2 324.__________ The melting point of MgO is higher than that of NaF. Explanations for this observation include which of the following? I. Mg2+ is more positively charged than Na+ II. O2- is more negatively charged than FIII. The O2- ion is smaller than the F- ion (A) II only (B) I and II only (C) I and III only (D) II and III only 325. __________ Which ionic compound has the highest melting point? (A) KCl (B) K2O (C) CaCl2 (D) CaO (E) I, II, and III (E) CaBr2 326. __________Which of the following substances can conduct electricity at room temperature? I. Mg II. CuCl2 III. Cu (A) II only (B) I and II only (C) I and III only (D) II and III only (E) I, II, and III 327. __________ What is the oxidation number of phosphorus in copper(II) phosphite? (A) +2 (B) +3 (C) -3 (D) +4 (E) +5 328. __________ Which of the following is true about ionic compounds? I. They are most crystalline solids at room temperature. II. They only conduct electricity when dissolved in water. III. They have free moving electrons. (A) I only (B) I and II only (C) I and III only (D) II and III only (E) I, II, and III 329. __________When LiF is formed from its elements there are five steps. Which of the following steps is NOT endothermic? I. Step 1: Sublimation of solid lithium. Li(s) Li(g) II. Step 2: Ionization of lithium atom. Li(g) Li+(g) + eIII . Step 4: Formation of fluoride ions. F(g) + e- F-(g) (A) II only (B) II only (C) I and II only (D) II and III only (E) III only 330. __________ Which of the following would likely have the highest melting point? (A) LiCl (B) LiF (C) NaCl (D) NaF (E) KF 331. __________ What is the oxidation number of sulfur in aluminum sulfate? (A) +3 (B) -2 (C) +2 (D) +4 (E) +6 332. __________ What is the oxidation number of manganese in MnO2? (A) +2 (B) +3 (C) +4 (D) +6 (E) +7 333. __________ What is the oxidation number of ruthenium in RuO3? (A) +3 (B) +2 (C) +6 (D) +4 (E) +8 334. ___________ Which of the following represents the ground state electron configuration for the Mn3+ ion? (A) 1s2 2s22p6 3s23p63d4 (B) 1s2 2s22p6 3s23p63d5 4s2 (C) 1s2 2s22p6 3s23p63d2 4s2 2 2 6 2 6 8 2 2 2 6 2 6 3 1 (D) 1s 2s 2p 3s 3p 3d 4s (E) 1s 2s 2p 3s 3p 3d 4s 335. ___________ The electron configuration: 1s2 2s2 2p6 3s2 3p6 corresponds to the electron configuration of: (A) S2(B) Ca2+ (C) Cl(D) K+ (E) all of these 336. ___________ Which of the following has the largest value for the second ionization energy? (A) sodium (B) chlorine (C) sulfur (D) aluminum (E) magnesium 337. ___________ Which of the following has the largest electron affinity? (A) sodium (B) chlorine (C) sulfur (D) aluminum (E) magnesium 338. ___________ In which of the following are the elements listed in order of increasing ionization energy? (A) B, Be, C, N (B) F, Cl, Br, I (C) O, N, C, B (D) Mg, Al, Si, P (E) N,O, F, Ne Ionization Energies for element X (kJ mol¯1) First Second Third Fourth Five 580 1815 2740 11600 14800 339. ___________ The ionization energies for element X are listed in the table above. On the basis of the data, element X is most likely to be: (A) Na (B) Mg (C) Al (D) Si (E) P 340. ___________ In which of the following are the elements listed in order of increasing Electronegativity? (A) Ba, Zn, C, Cl (B) N, O, S, Cl (C) N, P, As, Sb (D) K, Ba, Si, Ga (E) Li, K, Na, Ca 341. ___________ In the periodic table, as the atomic number increases from 11 to 17, what happens to the atomic radius? (A) It remains constant. (B) It increases only. (C) It increases, then decreases. (D) It decreases only. (E) It decreases, then increases. 342. ___________ Which of the following elements has one valence electron? (A) helium (B) chlorine (C) chromium (D) aluminum (E) zinc 343. ____________ One of the outermost electrons in a strontium atom in the ground state can be described by which of the following sets of four quantum numbers? (A) 5, 2, 0, ½ (B) 5, 1, 1, ½ (C) 5, 1, 0, ½ (D) 5, 0, 1, ½ (E) 5, 0, 0, ½ 344. ____________ Which type of radiation continues in a straight line when passed through an electric field? (A) alpha (B) gamma (C) beta (D) proton (E) positron 345. ____________ For the types of radiation given, which of the following is the correct order of increasing ability to penetrate a piece of lead? (A) Alpha particles < gamma rays < beta particles (B) Alpha particles < beta particles < gamma rays (C) Beta particles < alpha particles < gamma rays (D) Beta particles < gamma rays < alpha particles (E) Gamma rays < alpha particles < beta particles 346. ____________ Correct statements about alpha particles include which of the following? I. They have a mass number of 4 and a charge of +2. II. They are more penetrating than beta particles. III. They are helium nuclei. (A) I only (B) III only (C) I and II (D) I and III (E) II and III 347. ____________ If 87.5 percent of a sample of pure 131I decays in 24 days, what is the half-life of 131I? (A) 6 days (B) 8 days (C) 12 days (D) 14 days (E) 21 days 348. __________ . 235 92 U 1 + 0n 141 55 Cs 1 + 30n + X Neutron bombardment of uranium can induce the following reaction represented above. Nuclide X is which of the following? (A) 92 35 Br (B) 94 35 Br (C) 91 37 Rb (D) 92 37 Rb (E) 94 37 Rb 349. __________ Experiments performed to reveal the structure of atoms led scientists to conclude that an atom’s (A) positive charge is evenly distributed throughout its volume (B) negative charge is mainly concentrated in its nucleus (C) mass is evenly distributed throughout its volume (D) volume is mainly unoccupied (E) positive and negative charges are concentrated in the nucleus 350. __________ What is the maximum number of electrons that occupy the n = 3 level? (A) 6 (B) 8 (C) 10 (D) 18 (E) 32 351. __________ How many unpaired electrons are in an iron atom in its ground state? (A) 6 (B) 5 (C) 4 (D) 2 (E) 0 352. __________ An electron in an atom will emit energy (light) when it moves from energy level: (A) 2s to 2p (B) 1s to 2s (C) 2p to 3s (D) 2p to 1s (E) 3d to 4f 353. __________ How many orbitals in a ground state oxygen atom are completely filled? (A) 1 (B) 2 (C) 3 (D) 4 (E) 5 Use these answers for questions 354 - 356. (A) Wave nature of matter (B) Pauli exclusion principle (D) Aufbau Principle (E) Heisenberg uncertainty principle (C) Hund's rule 354. __________ Electrons are placed in orbitals, subshells and shells in order of increasing energy. 355. __________ States that the more accurately you know a particle’s position, the less accurately you can know its momentum and vice vers(A) 356. __________ Indicates that no two electrons in an atom may have the same four quantum numbers. 357. __________ Which of the following is an example of a physical change to a pure substance? (A) an apple reacting with oxygen and turning brown (B) sublimation of iodine (C) melting 6.0 grams of salt water (D) burning of coal 358. __________ Which of these is the percent of error in evaluating the molecular mass of a compound if the experimental value was 105.2 amu and the known value was 107.5 amu? (A) 1.0% (B) 2.1% (C) 3.3% (D) 4.2% 359. __________ Which set of equipment would be most useful to determine the density of a liquid? (A) Balance and periodic table (B) Periodic table and thermometer (C) Balance and graduated cylinder (D) Graduated cylinder and thermometer 360. __________ One serving of peanut butter is 36 grams. Which of the following is the same value in kilograms? (A) 3.6 x 10-4 (B) 3.6 x 10-3 (C) 3.6 x 10-2 (D) 3.6 x 104 361. __________ Which of the following is NOT an intensive property? (A) malleablity (B) good conductor of heat (C) density of 3.4 g/mL (D) mass of 32.0 grams 362. __________ Which of the following is an extensive property? (A) reacts with water (B) density of 3.0 g/mL (C) melts at 424 K (D) mass of 10.0 grams 363. __________ Which of the following measurements shows good precision & good accuracy, if the actual scientific value is 3.74 cm? (A) 2.75 cm, 3.75 cm , 4.05 cm (B) 3.76 cm, 3.76 cm, 3.75 cm (C) 4.02 cm, 4.02 cm, 4.01 cm (D) 4.52 cm. 4.78 cm, 3.01 cm 364. __________ Which separation technique would be used by someone stranded at sea to make salt water drinkable? (A) decanting (B) electrolysis (C) distillation (D) chromatography 365. __________ How many total significant figures would the solution to the following calculation have? 321.3 + 0.003 + 680. (A) 4 (B) 3 (C) 2 (D) 1 366. __________ Two solid objects are of equal volume, but object A has a density = X and object B has a density = (0.5)(X). Which of the following is true concerning objects A & B? (A) Object B has twice the density of object (A) (B) Objects A & B are of equal mass. (C) Object A has one half the mass of object (B) (D) Object A has twice the mass of object (B) 367. __________ Some bottles of colorless liquids were being labeled when the technicians accidentally mixed them up and lost track of their contents. A 15.0 mL sample withdrawn from one bottle weighed 22.3 g. Which of the following is the correct identity of the unknown liquid? (A) acetone, d=0.792 g/mL (B) benzene, 0.899 g/mL (C) chloroform, d=1.489 g/mL (D) carbon tetrachloride, d=1.595 g/mL 368. __________ The proper scientific notation for 565,000,000,000 is — (A) 0.565 x 109 (B) 5.65 x 1011 (C) 56.5 x 1011 (D) 565 x 1012 369. __________ Sublimation is an example of an: (A) exothermic chemical change (C) endothermic chemical change (B) endothermic physical change (D) exothermic physical change 370. __________ The graphite in a mechanical pencil has a size of 0.7 millimeters. What is this value in meters? (A) 7 x 103 (B) 7 x 10-3 (C) 7 x 10-2 (D) 7 x 10-4 371. __________ Many reactions are taken to completion by heating the reaction mixture in a test tube. Each of the following would be a safe practice except – (A) heating the test tube gently to prevent the solution from boiling over (B) pointing the test tube away from others so that no one is injured (C) placing a stopper in a test tube to prevent gas from escaping (D) holding the test tube with test tube clamps to avoid touching hot objects 372. __________ How many significant figures are there in 0.0090290 m? (A) 5 (B) 3 (C) 7 (D) 8 373. __________ A student measured the temperature of a boiling solution and found it to be 56.0C at standard pressure. The theoretical temperature of that boiling solution is 55.0(C) What is the percent of error in the student’s measurement? (A) 18% (B) 1.8% (C) 0.18% (D) 0.018% 374. __________ In order to determine the identity of a substance, a student listed the following properties. Which of the following is a chemical property? (A) Oxidizes in air (B) Conducts an electric current (C) Attraction to a magnet (D) Dissolves in water 375. __________ Which of the following would sink in water? (A) substance a, density 2.0 g/L (B) substance b, density 0.7 g/mL (C) substance c, density 1.1 g/mL (D) none of the above