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3 Chapter Stoichiometry of Formulas and Equations Created: 9:27:51 AM MST 1. Calcium fluoride, CaF2, is a source of fluorine and is used to fluoridate drinking water. Calculate its molar mass. A. B. C. D. E. 118.15 g/mol 99.15 g/mol 78.07 g/mol 59.08 g/mol 50.01 g/mol 5. Aluminum sulfate, Al2(SO4)3, is used in tanning leather, purifying water, and manufacture of antiperspirants. Calculate its molar mass. A. B. C. D. E. 450.06 g/mol 342.15 g/mol 315.15 g/mol 278.02 g/mol 74.98 g/mol 4.00 102 g 25.0 g 17.0 g 4.00 10-2 g 2.50 10-3 g 1.244 1023 O atoms 4.976 1023 O atoms 2.409 1024 O atoms 2.915 1024 O atoms 1.166 1025 O atoms 9. What is the mass in grams of 0.250 mol of the common antacid calcium carbonate? A. B. C. D. E. A. B. C. D. E. 13. Calculate the number of oxygen atoms in 29.34 g of sodium sulfate, Na2SO4. 23. Hydroxylamine nitrate contains 29.17 mass % N, 4.20 mass % H, and 66.63 mass O. If its molar mass is between 94 and 98 g/mol, what is its molecular formula? A. B. C. D. E. A. B. C. D. E. NH2O5 N2H4O4 N3H3O3 N4H8O2 N2H2O4 CrSi3 Cr2Si3 Cr3Si Cr3Si2 Cr2S 25. A compound containing chromium and silicon contains 73.52 mass percent chromium. Determine its empirical formula. 27. Terephthalic acid, used in the production of polyester fibers and films, is composed of carbon, hydrogen, and oxygen. When 0.6943 g of terephthalic acid was subjected to combustion analysis it produced 1.471 g CO2 and 0.226 g H2O. What is its empirical formula? A. B. C. D. E. C2H3O4 C3H4O2 C4H3O2 C5H12O4 C2H2O 31. Balance the following equation: B2O3(s) + HF(l) BF3(g) + H2O(l) A. B. C. D. B2O3(s) + 6HF(l) 2BF3(g) + 3H2O(l) B2O3(s) + H6F6(l) B2F6(g) + H6O3(l) B2O3(s) + 2HF(l) 2BF3(g) + H2O(l) B2O3(s) + 3HF(l) 2BF3(g) + 3H2O(l) E. B2O3(s) + 6HF(l) 2BF3(g) + 6H2O(l) 37. Aluminum will react with bromine to form aluminum bromide (used as an acid catalyst in organic synthesis). Al(s) + Br2(l) Al2Br6(s) [unbalanced] How many moles of Al are needed to form 2.43 mol of Al2Br6? A. B. C. D. E. 7.29 mol 4.86 mol 2.43 mol 1.62 mol 1.22 mol 43. Potassium chlorate (used in fireworks, flares and safety matches) forms oxygen and potassium chloride when heated. KClO3(s) KCl(s) + O2(g) [unbalanced] How many grams of oxygen are formed when 26.4 g of potassium chlorate is heated? A. B. C. D. E. 223 g 99.1 g 10.3 g 6.86 g 4.60 g 47. In a blast furnace, elemental iron is produced from a mixture of coke (C), iron ore (Fe3O4) and other reactants. An important reaction sequence is 2C(s) + O2(g) 2CO(g) Fe3O4(s) + 4CO(g) 3Fe(l) + 4CO2(g) How many moles of iron can be formed in this sequence when 1.00 mol of carbon, as coke, is consumed? A. B. C. D. E. 6.00 mol Fe 3.00 mol Fe 1.33 mol Fe 1.25 mol Fe 0.750 mol Fe 51. Magnesium (used in the manufacture of light alloys) reacts with iron(III) chloride to form magnesium chloride and iron. 3Mg(s) + 2FeCl3(s) 3MgCl2(s) + 2Fe(s) A mixture of 41.0 g of magnesium ( = 24.31 g/mol) and 175 g of iron(III) chloride ( = 162.2 g/mol) is allowed to react. Identify the limiting reactant and determine the mass of the excess reactant present in the vessel when the reaction complete. is A. B. C. D. E. Limiting reactant is Mg; 67 g of FeCl3 remain. Limiting reactant is Mg; 134 g of FeCl3 remain. Limiting reactant is Mg; 104 g of FeCl3 remain. Limiting reactant is FeCl3; 2 g of Mg remain. Limiting reactant is FeCl3; 87 g of Mg remain. 55. Methanol (CH4O) is converted to bromomethane (CH3Br) as follows: CH4O + HBr CH3Br + H2O If 12.23 g of bromomethane are produced when 5.00 g of methanol is reacted with excess HBr, what is the percentage yield? A. B. C. D. E. 40.9% 82.6% 100.% 121% 245% 59. Hydrochloric acid is widely used as a laboratory reagent, in refining ore for the production of tin and tantalum, and as a catalyst in organic reactions. Calculate the number of moles of HCl in 62.85 mL of 0.453 M hydrochloric acid. A. B. C. D. E. A. B. C. D. E. 28.5 mol 1.04 mol 0.139 mol 0.0285 mol 0.00721 mol 0.800 L 0.400 L 0.200 L 0.100 L none of these choices is correct 65. What volume, in L, of 10.0 M HCl is needed to make 2.00 L of 2.00 M HCl solution by dilution with water? 69. Propane, C3H8, is commonly provided as a bottled gas for use as a fuel. In 0.200 mol of propane a. what is the mass of propane? b. what mass of carbon is present? c. how many molecules of C3H8 are present? d. how many hydrogen atoms are present? 71. In 0.20 mole of phosphoric acid, H3PO4 a. how many H atoms are there? b. what is the total number of atoms? c. how many moles of O atoms are there? Balance the equation B2O3(s) + NaOH(aq) Na3BO3(aq) + H2O(l) 77. 79. 81. Gaseous methanol (CH4O) reacts with oxygen gas to produce carbon dioxide gas and liquid water.Write a balanced equation for this process. Ammonia, NH3 , is produced industrially from nitrogen and hydrogen as follows: N2(g) + 3H2(g) 2NH3(g) What mass, of which starting material, will remain when 30.0 g of N2 and 10.0 g of H2 react until the limiting reagent is completely consumed? The insecticide DDT was formerly in widespread use, but now it is severely restricted owing to its adverse environmental effects. It is prepared as follows: C2HCl3O + C6H5Cl C14H9Cl5 + H2O chloral chlorobenzene DDT If 10.00 g of chloral were reacted with 10.00 g of chlorobenzene a. what is the maximum amount (mol) of DDT which could be formed? b. what is the limiting reagent? c. what is the % yield, if 12.15 g of DDT is produced? Aluminum metal dissolved in hydrochloric acid as follows 2Al(s) + 6HCl(aq) 2AlCl3(aq) + 3H2(g) a. What is the minimum volume of 6.0 M HCl(aq) needed to completely dissolve 3.20 g of aluminum in this reaction? b. What mass of AlCl3 would be produced by complete reaction of 3.20 g of aluminum? 75. 85. 1. C 3. C 5. B 9. B 13. B 23. B 25. D 27. C 31. A 37. B 43. C 47. E 51. D 55. B 59. D C 65. B 69. a. 8.82 gb. 7.21 gc. 1.20 1023 C3H8 moleculesd. 9.64 1023 H atoms 71. (p. 92) a. 3.61 1023 H atomsb. 9.64 1023 atomsc. 4.82 1023 O atoms 75. (p. 101) B2O3(s) + 6NaOH(aq) 2Na3BO3(aq) + 3H2O(l) 77. (p. 101) 2CH4O(g) + 3O2(g) 2CO2(g) + 4H2O(l) 79. (p. 110) 3.52 g of hydrogen gas remains. 81. (p. Sec. 3.4) a. 0.0444 mol DDTb. Chlorobenzene is the limiting reagent.c. 77.2% 85. (p. 120) a. 59.3 mL b. 15.8 g ... View Full Document

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