This Document Contains Chapters 5 to 6 Chapter 5 Molecules and Compounds True/False Questions 1. When elements combine to form compounds, their properties only change slightly. Answer: False 2. The properties of a compound are an average of the properties of the individual elements. Answer: False 3. Life could not exist with just 91 elements if they did not combine to form compounds. Answer: True 4. Although some substances we encounter in our routine lives are elements, most occur in the combined state. Answer: True 5. The law of constant composition states: All samples of a given compound have the same proportions of their constituent elements. Answer: True 6. The fact that water has an oxygen-to-hydrogen mass ratio of 8.0 illustrates the law of conservation of mass. Answer: False 7. The subscripts in a chemical formula represent the relative mass of each atom in a chemical compound. Answer: False 8. The subscripts in a chemical formula do not change for a given compound. Answer: True 9. Chemical formulas normally list the most metallic elements first. Answer: True 10. The formula of a compound comprised of two nitrogen atoms and one oxygen atom should be written properly as ON2. Answer: False 11. Molecular elements do not exist in nature. Answer: False 12. The element nitrogen normally exists in nature as a diatomic molecule. Answer: True 13. Carbon dioxide is an example of a molecular compound. Answer: True 14. The basic unit of an ionic compound is called the formula unit. Answer: True 15. SO2 is an ionic compound. Answer: False 16. Ionic compounds have a net charge of zero. Answer: True 17. Ionic compounds always contain positive and negative ions. Answer: True 18. In ionic compounds the net positive charge always equals the net negative charge. Answer: True 19. The ionic compound that forms between aluminum and oxygen is AlO. Answer: False 20. The ionic compound that forms between Mg and O is MgO. Answer: True 21. The correct formula for calcium fluoride is CaF3. Answer: False 22. Ionic compounds are usually made up of a metal and a nonmetal. Answer: True 23. The ionic compound MgO is named manganese oxide. Answer: False 24. The name of KNO3 is potassium nitratide. Answer: False 25. The correct formula for sodium permanganate is NaMgO4. Answer: False 26. Type II metal cations are usually found in the section of the periodic table known as the transition metals. Answer: True 27. If there are two ions in a series of oxoanions, the one with more oxygen is given the ending "-ite." Answer: False 28. The proper name for SF6 is sulfur tetrafluoride. Answer: False 29. The proper name for the acid HF is hydrofluoric acid. Answer: True 30. The proper name for for HI is hydroiodic acid. Answer: True 31. The correct name for HNO3 is hydronitric acid. Answer: False 32. The correct name for H2SO3 is sulfurous acid. Answer: True Multiple Choice Questions 33. When elements combine to form compounds, A) their properties are an average of all elements in the compound. B) their properties change completely. C) their properties do not change. D) their properties are completely random. E) none of the above Answer: B 34. The first chemist to formally state the law of constant composition was __________. A) Dalton B) Mendeleev C) Rutherford D) Proust E) none of the above Answer: D 35. The law of constant composition states: A) Matter cannot be either created or destroyed in a chemical reaction. B) The nucleus is a dense region of positive charge that always contains protons and neutrons. C) All samples of a given compound have the same proportions of their constituent elements. D) All atoms of a given element have a constant composition and are different than atoms of any other element. E) none of the above Answer: C 36. The oxygen-to-hydrogen mass ratio of water is always 8.0 is an example of what fundamental law? A) Law of Constant Composition B) Law of Constant Mass Ratio C) Law of Conservation of Mass D) Law of Constant Whole Number Ratio E) none of the above Answer: A 37. What is the oxygen-to-hydrogen mass ratio for H2O2? A) 0.125 B) 4 C) 8 D) 16 E) none of the above Answer: D 38. The phosphorous-to-hydrogen mass ratio is 10.2 for a compound. This ratio could correspond to the compound A) PH. B) PH2. C) PH3. D) PH6. E) none of the above Answer: C 39. What is the oxygen-to-sulfur mass ratio of sulfur dioxide? A) 0.5 B) 1.0 C) 2.0 D) 16 E) none of the above Answer: B 40. Which of the following statements about chemical formulas is FALSE? A) The subscripts represent the relative number of each type of atom in the compound. B) The subscripts represent the relative mass of each type of atom in the compound. C) The subscripts do not change for a given compound. D) Different compounds made of the same elements have different subscripts. E) All of the statements are true. Answer: B 41. How many total atoms are in the formula Al2(CO3)3? A) 8 B) 9 C) 12 D) 14 E) none of the above Answer: D 42. How many carbon atoms are in the formula Al2(CO3)3? A) 3 B) 9 C) 1 D) 6 E) none of the above Answer: A 43. How many oxygen atoms are in the formula Al2(CO3)3? A) 3 B) 9 C) 1 D) 6 E) none of the above Answer: B 44. Which formula shows the proper use of parentheses? A) Ca(F)2 B) Ca(SO4) C) (NH4)3(PO4) D) Ca(NO3)2 E) none of the above Answer: D 45. How many of each type of atoms are there in the formula NH4C2H3O2? A) N = 4, H = 7, C = 2, O = 2 B) N = 1, H = 4, C = 2, O = 2 C) N = 1, H = 3, C = 2, O = 2 D) N = 1, H = 7, C = 2, O = 2 E) none of the above Answer: D 46. How many of each type of atom are there in the formula Ca3(PO4)2? A) Ca = 3, P = 1, O = 4 B) Ca = 3, P = 2, O = 4 C) Ca = 3, P = 2, O = 8 D) Ca = 3, P = 1, O = 8 E) none of the above Answer: C 47. How many of each type of atom are there in the formula (NH4)2HPO4? A) N = 2, H = 9, P = 1, O = 4 B) N = 1, H = 5, P = 1, O = 4 C) N = 2, H = 5, P = 1, O = 4 D) N = 2, H = 8, P = 1, O = 4 E) none of the above Answer: A 48. What is the correct formula for a compound that has three oxygen atoms and one sulfur atom? A) O3S B) SO3 C) 3OS D) SO3 E) none of the above Answer: B 49. What is the correct formula of a compound that has ten oxygen atoms and four phosphorus atoms? A) O10P4 B) 10OP4 C) 4PO10 D) P4O10 E) none of the above Answer: D 50. Carbon is considered which of the following? A) atomic element B) molecular element C) molecular compound D) ionic compound E) none of the above Answer: A 51. Which among the following elements does NOT exist as a diatomic molecule in nature? A) hydrogen B) nitrogen C) fluorine D) neon E) none of the above Answer: D 52. Carbon monoxide is considered which of the following? A) atomic element B) molecular element C) molecular compound D) ionic compound E) none of the above Answer: C 53. Fluorine is considered which of the following? A) atomic element B) molecular element C) molecular compound D) ionic compound E) none of the above Answer: B 54. Ammonium fluoride is considered which of the following? A) atomic element B) molecular element C) molecular compound D) ionic compound E) none of the above Answer: D 55. Which of the following species is a molecular element? A) neon B) sodium C) chlorine D) carbon dioxide E) none of the above Answer: C 56. Which of the following is a molecular compound? A) barium sulfide B) calcium acetate C) potassium hydroxide D) nitrogen monoxide E) none of the above Answer: D 57. What is the formula for an ionic compound made of barium and nitrogen? A) Ba3N2 B) Ba2N3 C) BaN D) Ba2N4 E) none of the above Answer: A 58. What is the formula for an ionic compound made of magnesium and sulfur? A) MgS B) MgS2 C) Mg2S D) Mg2S3 E) none of the above Answer: A 59. What is the formula for an ionic compound made of carbon and oxygen? A) CO2 B) C2O C) CO D) CO3 E) Carbon and oxygen do not form an ionic compound. Answer: E 60. The ionic compound that forms between potassium and oxygen is A) K2O. B) KO. C) KO2. D) K2O2. E) none of the above Answer: A 61. What is the formula for an ionic compound made of aluminum and oxygen? A) AlO2 B) Al2O3 C) Al3O2 D) AlO E) none of the above Answer: B 62. What is the name of the ionic compound made of beryllium and chlorine? A) beryllium(II) chloride B) beryllium dichloride C) beryllium chloride D) monoberyllium dichloride E) none of the above Answer: C 63. What is the name of the compound made from lithium and oxygen? A) lithium dioxide B) lithium(I) oxide C) oxygen lithide D) lithium oxide E) none of the above Answer: D 64. Which metal atom below would NOT be involved in formation of a Type II compound? A) Cr B) Mn C) Fe D) Ba E) none of the above Answer: D 65. What is the name of CoS? A) cobalt(II) sulfide B) cobalt sulfide C) cobalt monosulfide D) cobaltous sulfur E) none of the above Answer: A 66. What is the name of Ca(NO3)2? A) calcium dinitrite B) calcium nitrate C) calcium nitride D) calcium nitrite E) none of the above Answer: B 67. Which formula shown is incorrect for the name given? A) magnesium nitrite: Mg(NO2)3 B) calcium carbonate: CaCO3 C) aluminum sulfate: Al2(SO4)3 D) sodium hydrogen carbonate: NaHCO3 E) potassium hydroxide: KOH Answer: A 68. Which formula shown is incorrect for the name given? A) strontium carbonate: SrCO3 B) ammonium cyanide: NH4CN C) potassium acetate: KC2H3O2 D) calcium nitrate: Ca(NO3)2 E) lithium sulfate: LiSO4 Answer: E 69. What is the name of the compound whose formula is Na2O? A) sodium monoxide B) disodium oxide C) disodium monoxide D) sodium oxide E) none of the above Answer: D 70. What is the formula for the acetate polyatomic ion? A) C3H2O3- B) C2H3O22- C) C2H3O2- D) C2H3O- E) none of the above Answer: C 71. What is the correct formula for potassium dichromate? A) K(CrO4)2 B) KCr2O7 C) K2CrO4 D) K2Cr2O7 E) none of the above Answer: D 72. What is the correct formula for ammonium hydrogen sulfate? A) NH4HSO4 B) (NH4)2HSO4 C) (NH4)2SO4 D) Am2HSO4 E) none of the above Answer: A 73. The formula for potassium chlorate is KClO3. The formula for magnesium chloride is MgCl2. What is the formula for magnesium chlorate? A) MgClO3 B) Mg2ClO3 C) Mg(ClO3)2 D) Mg2(ClO3)3 E) none of the above Answer: C 74. The charge of a vanadium ion in the compound V2O5 is: A) 5+ B) 2+ C) 10+ D) 10- E) none of the above Answer: A 75. What is the correct formula for the hypochlorite polyatomic ion? A) ClO- B) ClO2- C) ClO3- D) ClO4- E) none of the above Answer: A 76. What is the correct name for the BrO41- ion? A) hypobromite B) perbromate C) bromite D) bromate E) none of the above Answer: B 77. Choose the pair of names and formulas that do NOT match. A) copper(I) nitrate: CuNO3 B) copper(II) nitride: Cu3N2 C) copper(II) nitrate: Cu(NO3)2 D) copper(II) nitrite: Cu(NO2)2 E) all of these are correct Answer: E 78. The name trisodium phosphate is incorrect for the compound Na3PO4 because A) this compound should be called trisodium monophosphate. B) the sodium has a negative 3 charge. C) you cannot use a prefix for the first element in a molecular compound. D) you cannot use a prefix for the first element of an ionic compound. E) none of the above Answer: D 79. What is the name of the molecular compound SF5? A) sulfur hexafluoride B) sulfur heptafluoride C) monosulfur tetrafluoride D) sulfur pentafluoride E) none of the above Answer: D 80. What is the name of the molecular compound SO3? A) sulfur oxide B) sulfur(IV) oxide C) sulfur trioxide D) sulfur tetraoxide E) none of the above Answer: C 81. What is correct name of the compound whose formula is N2O4? A) nitrogen dioxide B) nitrogen tetroxide C) dinitrogen oxide D) dinitrogen tetroxide E) none of the above Answer: D 82. What is correct name of the compound whose formula is BF3? A) boron trifluoride B) boron fluoride C) monoboron trifluorine D) boron(III) fluoride E) none of the above Answer: A 83. What would the formula of diiodine pentasulfide be? A) I5S2 B) I2S5 C) I4S9 D) I2S7 E) none of the above Answer: B 84. What is the correct formula for the molecular compound heptaphosphorus octafluoride? A) P5F8 B) P 7F6 C) P6F7 D) P7F8 E) none of the above Answer: D 85. What is the proper name for HBr (aq)? A) hydrobromous acid B) hydrousbromic acid C) hydrobromic acid D) bromous acid E) none of the above Answer: C 86. What is the name of HI (aq)? A) hydroiodous acid B) hydroiodic acid C) iodic acid D) iodous acid E) none of the above Answer: B 87. What is the name of HIO3? A) iodic acid B) hydroioidic acid C) hydroiodous acid D) iodous acid E) none of the above Answer: A 88. What is the name of HNO2? A) Nitric acid B) Nitrous acid C) hydronitrous acid D) hydronitric acid E) none of the above Answer: B 89. A certain oxyacid is derived from the oxyanion SO32-. The formula for the oxyacid is A) H2SO4. B) HSO3. C) H2SO3. D) H3SO3. E) none of the above Answer: C 90. What is the formula mass of sulfurous acid? A) 82.08 amu B) 98.08 amu C) 83.09 amu D) 66.08 amu E) none of the above Answer: A 91. What is the formula mass for potassium nitrate? A) 92.99 amu B) 117.11 amu C) 85.11 amu D) 101.10 amu E) none of the above Answer: D 92. What is the formula mass for diboron tetrachloride? A) 127.98 amu B) 198.89 amu C) 234.34 amu D) 163.43 amu E) none of the above Answer: D 93. What is the formula mass of copper(II) fluoride? A) 101.55 B) 146.10 C) 90.00 D) 165.10 E) none of the above Answer: A 94. Which of the following has the largest formula mass? A) CO2 B) SO2 C) NO2 D) SiO2 E) H2O Answer: B 95. Which of the following compounds have the smallest formula mass? A) CO2 B) SO2 C) NO2 D) SiO2 E) H2O Answer: E 96. A compound has a formula mass of 61.98 amu and is comprised of atoms of sodium and oxygen in a definite ratio. The name of the compound described here is A) sodium monoxide. B) disodium oxide. C) sodium oxide. D) sodium dioxide. E) none of the above Answer: C Algorithmic Questions 97. What is the mass ratio of Na to S in sodium sulfide? A) 7.17 B) 55.06 C) 0.717 D) 1.43 E) none of the above Answer: D 98. If the mass ratio of K to F in a compound is 2.06:1, how many grams of F are needed to react with 97.5 g of K? A) 0.0211 B) 47.3 C) 4.73 D) 2.11 E) none of the above Answer: B 99. How many C atoms are in ammonium acetate? A) 5 B) 2 C) 1 D) 3 E) none of the above Answer: B 100. How many O atoms are present in sodium chlorite? A) 2 B) 6 C) 4 D) 1 E) none of the above Answer: A 101. What is the formula mass of magnesium sulfide? A) 88.45 B) 80.69 C) 56.4 D) 144.83 E) none of the above Answer: C Chapter 6 Chemical Composition True/False Questions 1. The chemical formula clearly indicates the relationship between the mass of each element in the formula. Answer: False 2. Mass is used as a method of counting atoms. Answer: True 3. The numerical value of the mole is defined as being equal to the number of atoms in exactly 12 grams of pure carbon-12. Answer: True 4. The mole has a value of 6.023 × 1022. Answer: False 5. Avogadro's Number is 6.022 × 1023. Answer: True 6. The number 6.022 × 1023 is six times larger than the number 6.022 × 1022. Answer: False 7. The lighter the atom, the less mass in one mole of that atom. Answer: True 8. One mole of argon has more atoms in it than one mole of neon. Answer: False 9. One mole of nitrogen gas contains (2) × (6.022 × 1023) nitrogen atoms. Answer: True 10. One mole of copper atoms is 6.022 × 1023 copper atoms. Answer: True 11. One mole of chlorine gas has a mass of 35.45 grams. Answer: False 12. One mole of zinc contains 65.39 zinc atoms. Answer: False 13. One mole of I2 has more atoms in it than one mole of Na. Answer: True 14. Two moles of cobalt atoms have a mass of 117.87 grams. Answer: True 15. Six grams of carbon contains 3.008 × 1023 atoms. Answer: True 16. The mass of 2.0 moles of H2O is greater than the mass of 1.0 mole of CO2. Answer: False 17. One mole of CO2 gas contains 1 mole of carbon atoms and 2 moles of oxygen atoms. Answer: True 18. One mole of water contains 16 grams of oxygen atoms. Answer: True 19. One mole of water contains 6.022 × 1023 hydrogen atoms. Answer: False 20. One mole of lead(II) nitrate contains six moles of oxygen atoms. Answer: True 21. The chemical formula CuBr2 indicates that this compound is composed of 1 gram of copper and 2 grams of bromine. Answer: False 22. There are 6 grams of carbon in 22 grams of carbon dioxide. Answer: True 23. The molar mass of a compound serves as a conversion factor between grams and moles. Answer: True 24. The correct formula for calculating mass percent of X in compound XY is: Mass of X in a sample of the compound/Mass of Y in a sample of the compound = Mass % X Answer: False 25. Water is 11.2% hydrogen by mass. Answer: True 26. C2H3O2 could be an empirical formula. Answer: True 27. C2H6O3 could be an empirical formula. Answer: True 28. An empirical formula gives the specific number of each type of atom in a molecule. Answer: False 29. An empirical formula gives the smallest whole number ratio of each type of atom in a molecule. Answer: True 30. C2H6O4 could be an empirical formula. Answer: False 31. The empirical formula for C6H6 is C3H3. Answer: False 32. The molecular formula is equal to the empirical formula multiplied by a whole number integer. Answer: True 33. The empirical formula mass is 18.0 and the molecular formula mass is 90, therefore n = 5. Answer: True 34. The empirical formula mass must be 25.0 if the molecular formula mass is 250 and n = 5. Answer: False 35. A molecule that has an empirical formula of HO and a molar mass of 34.02 gram must have a molecular formula of H2O2. Answer: True Multiple Choice Questions 36. What is the correct value for Avogadro's number? A) 6.022 × 1023 B) 6.022 × 1033 C) 6.023 × 1022 D) 6.022 × 102.3 E) none of the above Answer: A 37. Which of the following statements about the mole is FALSE? A) The size of a mole of atoms has a reasonable mass. B) A mole of a monatomic element corresponds to one Avogadro's number of atoms. C) One mole of a monatomic element has a mass equal to its atomic mass expressed in grams. D) One mole of water contains 1/2 mole of oxygen atoms. E) none of the above Answer: D 38. How many atoms are in 5.80 moles of He? A) 6.02 × 1023 B) 1.03 × 1023 C) 4.00 D) 3.49 × 1024 E) none of the above Answer: D 39. How many atoms are in 1.50 moles of fluorine gas? A) 6.022 × 1023 B) 9.03 × 1023 C) 18.98 D) 1.81 × 1024 E) none of the above Answer: D 40. How many moles of Cu are in 1.48 × 1025 Cu atoms? A) 0.0408 B) 24.6 C) 1.54 × 1025 D) 6.022 × 1023 E) none of the above Answer: B 41. How many moles of Pb are in 4.71 × 1021 Pb atoms? A) 0.00782 B) 2.84 × 1045 C) 207.2 D) 6.022 × 1023 E) none of the above Answer: A 42. One mole of boron has a mass of ________ g. A) 9.012 B) 6.022 × 1023 C) 5 D) 10.811 E) none of the above Answer: D 43. One mole of oxygen gas has a mass of ________ g. A) 16.0 B) 32.0 C) 6.022 × 1023 D) 8 E) none of the above Answer: B 44. What is the mass in grams of 5.40 moles of lithium? A) 6.94 B) 37.5 C) 1.29 D) 3.25 × 1024 E) none of the above Answer: B 45. What is mass of 0.560 moles of chlorine gas? A) 19.9 B) 63.3 C) 127 D) 39.7 E) none of the above Answer: D 46. You have 10.0 g each of Na, C, Pb, Cu and Ne. Which contains the largest number of moles? A) Na B) C C) Pb D) Cu E) Ne Answer: B 47. You have 10.0 g each of Na, C, Pb, Cu and Ne. Which contains the smallest number of moles? A) Na B) C C) Pb D) Cu E) Ne Answer: C 48. How many moles of iron are contained in 1.75 kg of iron? A) 3.13 × 10-2 B) 3.13 × 10-4 C) 31.3 D) 3.13 × 104 E) none of the above Answer: C 49. How many moles are there in 17.5 grams of sodium? A) 22.99 B) 1.05 × 1025 C) 0.761 D) 1.31 E) none of the above Answer: C 50. How many moles are there in 82.5 grams of iron? A) 4.97 × 1025 B) 55.85 C) 0.677 D) 1.48 E) none of the above Answer: D 51. How many moles of bromine gas are in 37.7 grams? A) 0.236 B) 0.472 C) 3.01 × 103 D) 79.9 E) none of the above Answer: A 52. How many atoms are in 15.6 grams of silicon? A) 2.64 × 1026 B) 3.34 × 1023 C) 0.555 D) 438 E) none of the above Answer: B 53. How many hydrogen atoms are in 35.0 grams of hydrogen gas? A) 4.25 × 1025 B) 2.09 × 1025 C) 2.12 × 1025 D) 1.05 × 1025 E) none of the above Answer: D 54. Which of the following contains 9.02 × 1023 atoms? A) 4.00 g H2 B) 9.00 g H2O C) 28.0 g N2 D) 32.0 g O2 E) none of the above Answer: B 55. What is the mass of 3.09 × 1024 atoms of sulfur in grams? A) 9.64 × 1022 B) 9.91 × 1025 C) 165 D) 0.160 E) none of the above Answer: C 56. What is the mass of 1.56 × 1021 atoms of magnesium in grams? A) 4.72 × 10-5 B) 0.0630 C) 0.142 D) 1.07 × 10-4 E) none of the above Answer: B 57. The mass of one mole of carbon dioxide is ____________ g. A) 28.01 B) 384.4 C) 32.00 D) 44.01 E) none of the above Answer: D 58. In comparing 1 mole of carbon atoms to one mole of magnesium atoms, which statement is TRUE? A) The mass of 1 mole of carbon is greater than the mass of 1 mole of magnesium. B) The mass of 1 mole of magnesium is greater than the mass of 1 mole of carbon. C) The mass of 1 mole of carbon is the same as the mass of 1 mole of magnesium. D) There are more atoms in 1 mole of magnesium than in 1 mole of carbon. E) none of the above Answer: B 59. In comparing a balloon containing 25 grams of helium to a balloon containing 25 grams of neon, which one of the following statements is TRUE? A) Each balloon has an equal number of atoms. B) The helium balloon has more atoms. C) The neon balloon has more atoms. D) This scenario cannot happen because gases have no mass. E) none of the above Answer: B 60. How many molecules of sulfur trioxide are in 78.0 grams? A) 5.87 × 1023 B) 7.33 × 1023 C) 3.76 × 1027 D) 0.974 E) none of the above Answer: A 61. How many molecules of nitrogen monoxide are in a 22.5 gram sample? A) 5.86 × 1023 B) 7.33 × 1023 C) 4.51 × 1023 D) 4.06 × 1023 E) none of the above Answer: C 62. If 3.011 × 1023 molecules have a mass of 20.04 grams, what is the molar mass of this substance? A) 40.08 g/mol B) 10.02 g/mol C) 20.04 g/mol D) 6.658 × 10-23 g/mol E) none of the above Answer: A 63. If 2.01 × 1023 atoms of an element from Group IA of the periodic table has a mass of 7.675 grams, this element is most likely A) Li. B) Na. C) K. D) Rb. E) Cs. Answer: B 64. One mole of (NH4)2HPO4 contains how many moles of hydrogen atoms? A) 4 B) 2 C) 8 D) 9 E) none of the above Answer: D 65. One mole of ammonium nitrate contains: A) 3 moles of hydrogen. B) 2 moles of oxygen. C) 2 moles of nitrogen. D) 1 mole of nitrogen. E) none of the above Answer: C 66. One mole of ammonium nitrite contains: A) 2 moles of nitrogen atoms. B) 4 moles of hydrogen atoms. C) 2 moles of oxygen atoms. D) All of A, B, and C. E) None of A, B, and C. Answer: D 67. One mole of potassium sulfate contains: A) 4 moles of oxygen. B) 2 moles of sulfur. C) 1 mole of potassium. D) 3 moles of potassium. E) none of the above Answer: A 68. Calculate the molar mass of ammonium carbonate. A) 78.05 g/mol B) 88.05 g/mol C) 96.09 g/mol D) 112.09 g/mol E) none of the above Answer: C 69. Calculate the molar mass of calcium nitrate. A) 136.03 g/mol B) 102.09 g/mol C) 132.10 g/mol D) 164.10 g/mol E) none of the above Answer: D 70. What is the molar mass of aluminum sulfate? A) 123.0 g/mol B) 278.0 g/mol C) 306.2 g/mol D) 315.2 g/mol E) 342.2 g/mol Answer: E 71. How many moles of carbon are in 3.5 moles of calcium carbonate? A) 10.5 B) 3.5 C) 7 D) 100.09 E) none of the above Answer: B 72. How many moles of fluorine are in 3.2 moles of xenon hexafluoride? A) 22.4 B) 12.8 C) 19.2 D) 16 E) none of the above Answer: C 73. If a sample of carbon dioxide contains 3.8 moles of oxygen atoms, how many moles of carbon dioxide are in the sample? A) 1.9 B) 3.8 C) 7.6 D) 11.4 E) none of the above Answer: A 74. A 15.5 gram sample of diphosphorous pentoxide contains how many grams of phosphorous? A) 3.38 B) 1.69 C) 6.76 D) 13.5 E) none of the above Answer: C 75. A 42.7 gram sample of potassium nitrate contains how many grams of potassium? A) 39.1 B) 16.5 C) 21.4 D) 8.54 E) none of the above Answer: B 76. An iron ore sample is found to be 35.00% Fe by mass. How many grams of ore are needed to obtain 454.0 gram of Fe? A) 1297 B) 158.9 C) 295.1 D) 350.0 E) none of the above Answer: A 77. A 500. gram iron ore sample was determined to contain 242 grams of iron. What is the mass percent of iron in the ore? A) 93.7 B) 48.4 C) 51.6 D) 32.6 E) none of the above Answer: B 78. Bauxite is an ore that contains the element aluminum. If you obtained 108 grams of aluminum from an ore sample that initially weighed 204 grams, what is the mass percent of aluminum in this bauxite ore? A) 52.9 B) 15.6 C) 0.53 D) 47.1 E) none of the above Answer: A 79. What is the mass percent of hydrogen in water? A) 33.3 B) 88.8 C) 5.60 D) 11.2 E) none of the above Answer: D 80. What is the mass percent of chlorine in hydrochloric acid? A) 2.8 B) 35.5 C) 97.2 D) 70.1 E) none of the above Answer: C 81. What is the mass percent of carbon in oxalic acid, H2C2O4? A) 2.24 B) 13.3 C) 26.7 D) 34.5 E) none of the above Answer: C 82. Which of the following compounds has the highest mass percent of "O"? A) MnO B) MnO2 C) Mn2O3 D) Mn3O2 E) none of the above Answer: B 83. Which of the following statements about empirical formulas is incorrect? A) An empirical formula represents a molecule. B) An empirical formula gives the smallest whole number ratio of each type of atom in a molecule. C) An empirical formula must be multiplied by an integer to obtain the molecular formula. D) The molecular formula can be the same as the empirical formula in some situations. E) All statements are correct. Answer: A 84. The empirical formula of a compound: A) describes the mass relationships in a molecule. B) is the same as the molecular formula. C) indicates the structure of the molecule. D) indicates the simplest ratio of atoms in the compound. E) none of the above Answer: D 85. The simplest formula for hydrogen peroxide is HO. To determine its molecular formula, it is necessary to know A) the properties of hydrogen peroxide. B) the density of hydrogen peroxide. C) the molar mass of hydrogen peroxide. D) the number of moles of hydrogen peroxide in 1.00 g of the substance. E) none of the above Answer: C 86. Which of the following is already in its empirical formula? A) C22H34O10 B) C6H6 C) C6H12O3 D) C5H12O2 E) none of the above Answer: D 87. The chemical formula CH2O can be classified as: A) not enough information B) molecular only. C) empirical only. D) empirical, possibly molecular. E) none of the above Answer: D 88. A chromium oxide compound contains 104.0 grams of chromium and 48.0 grams of oxygen. What is the most likely empirical formula of this compound? A) CrO B) CrO2 C) CrO3 D) Cr2O3 E) Cr3O2 Answer: D 89. An iron chloride compound contains 55.85 grams of iron and 106.5 grams of chlorine. What is the most likely empirical formula for this compound? A) FeCl B) FeCl2 C) Fe2Cl D) FeCl3 E) Fe3Cl Answer: D 90. A 7.96 gram sample of silver reacts with oxygen to form 8.55 gram of the metal oxide. What is the formula of the oxide? A) AgO B) AgO2 C) Ag2O D) Ag3O E) none of the above Answer: C 91. Determine the empirical formula of a compound containing 60.3% magnesium and 39.7% oxygen. A) MgO B) MgO2 C) Mg2O3 D) Mg2O E) none of the above Answer: A 92. Determine the empirical formula of a compound containing 83% potassium and 17.0% oxygen. A) KO B) KO2 C) K2O3 D) K2O E) none of the above Answer: D 93. Vitamin C is known chemically by the name ascorbic acid. Determine the empirical formula of ascorbic acid if it is composed of 40.92% carbon, 4.58% hydrogen, and 54.50% oxygen. A) CHO B) CH2O C) C2H3O2 D) C3H4O3 E) none of the above Answer: D 94. Determine the correct empirical formula of a compound containing 26.68% carbon, 2.24% hydrogen, and 71.08% oxygen. A) CHO B) CHO2 C) C0.5H0.5O1 D) C2H2O4 E) none of the above Answer: B 95. What is the molecular formula of a compound given the molar mass of the compound is 186.5 grams and the empirical formula is C2H7? A) C4H14 B) C3H21 C) C2H7 D) C2H14 E) none of the above Answer: E 96. An estrogen compound with the empirical formula C12H17O2 has a molecular mass of 386.6 g/mol. What is the value of n necessary to find the molecular formula? A) 0.2 B) 1 C) 2 D) 20 E) none of the above Answer: C 97. What is the value of n when the empirical formula is C3H5 and the molecular mass is 205.4 g/mol? A) 0.02 B) 5 C) 10 D) 140 E) none of the above Answer: B 98. What would the empirical formula be for the molecular compound C6H9O4? A) C2H3O2 B) CH3O2 C) C3H6O2 D) C3H9O4 E) none of the above Answer: E 99. What is the molecular formula of a compound given the molar mass of the compound is 30.04 gram and the empirical formula is NH? A) NH B) N2H2 C) N2H6 D) N4H4 E) none of the above Answer: B 100. A compound has a molar mass of 180.15 g/mol. Given the following percent composition, calculate the molecular formula: A) CH3O2 B) CH2O C) C3H6O3 D) C6H12O6 E) none of the above Answer: D 101. An unknown acid has a molar mass of 60.05 g/mol. Given the following percent composition, what is the molecular formula? 40% C, 6.7% H, 53.3% O A) C3H4O3 B) CH2O C) C2H4O2 D) C6H12O6 E) none of the above Answer: C Algorithmic Questions 102. Bananas cost 33¢ per pound. If you spent $0.77, how many pounds of bananas did you purchase? A) 2.33 B) 1.73 C) 0.429 D) 2.01 E) none of the above Answer: A 103. How many atoms are present in 2.5 moles? A) 6.6 x 1023 B) 6.6 x 10-25 C) 1.5 x 1024 D) 6.02 x 1023 E) none of the above Answer: C 104. If you have 1.81 x 1024 atoms of copper, how many moles of copper do you have? A) 0.330 B) 3.00 C) 0.750 D) 2.00 E) none of the above Answer: B 105. What is the mass of 3.91 x 1024 sulfur atoms? A) 208 B) 4.93 C) 155 D) 32.07 E) none of the above Answer: A 106. How many moles of potassium are in 156.4 g? A) 39.10 B) 4.000 C) 0.2500 D) 5.050 E) none of the above Answer: B 107. How many atoms of lithium are in 11.8 g? A) 1.35 x 1024 B) 1.70 x 1024 C) 1.02 x 1024 D) 2.22 x 1024 E) none of the above Answer: C 108. How many moles of oxygen are in 3.70 moles of NaClO4? A) 3.70 B) 0.270 C) 21.5 D) 14.8 E) none of the above Answer: D 109. What is the mass percent of Mg in magnesium chloride? A) 12.3 B) 40.7 C) 25.6 D) 68.3 E) none of the above Answer: C 110. What is the mass percent of oxygen in sodium oxide? A) 17.0 B) 25.8 C) 44.4 D) 39.7 E) none of the above Answer: B 111. Given that sodium chloride is 39.0% sodium by mass, how many grams of sodium chloride are needed to have 750. mg of Na present? A) 1.92 B) 0.293 C) 1,920 D) 29.3 E) none of the above Answer: A Test Bank for Introductory Chemistry Nivaldo J. Tro 9780321741028, 9780321687937, 9781256112938, 9781256161066, 9780134302386, 9780321910073
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