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Unformatted text preview: nanni (arn437) HW 03 Mixtures and Kinetic Theory vanden bout (50985) 1 This printout should have 19 questions. Multiplechoice questions may continue on the next column or page find all choices before answering. 001 (part 1 of 4) 10.0 points Iron pyrite (FeS 2 ) is the form in which much of the sulfur exists in coal. In the combustion of coal, oxygen reacts with iron pyrite to produce iron(III) oxide and sulfur dioxide, which is a major source of air pollution and a substantial contributor to acid rain. What mass of Fe 2 O 3 is produced from the reaction is 62 L of oxygen at 3 . 27 atm and 165 C with an excess of iron pyrite? Correct answer: 163 . 774 g. Explanation: P = 3 . 27 atm T = 165 C + 273 = 438 K R = 0 . 08206 L atm K mol V = 62 L MW Fe 2 O 3 = 2(55 . 845 g / mol) + 3(15 . 9994 g / mol) = 159 . 688 g / mol The balanced equation is 4 FeS 2 (s) + 11 O 2 (g) 2 Fe 2 O 3 (s) + 8 SO 2 (g) Applying the ideal gas law to the O 2 , P V = nRT n = P V RT = (3 . 27 atm) (62 L) ( . 08206 L atm K mol ) (438 K) = 5 . 64071 mol . From stoichiometry and the molar mass of Fe 2 O 3 , m Fe 2 O 3 = (159 . 688 g / mol Fe 2 O 3 ) 2 mol Fe 2 O 3 11 mol O 2 (5 . 64071 mol O 2 ) = 163 . 774 g Fe 2 O 3 . 002 (part 2 of 4) 10.0 points If the sulfur dioxide that is generated above is dissolved to form 6 . 6 L of aqueous solu tion, what is the molar concentration of the resulting sulfurous acid (H 2 SO 3 ) solution? Correct answer: 0 . 621566 M. Explanation: V = 6 . 6 L SO 2 (g) + H 2 O( ) H 2 SO 3 (aq) . From the stoichiometry, n SO 2 = (5 . 64071 mol) parenleftbigg 8 n SO 2 11 n O 2 parenrightbigg = 4 . 10233 mol . 4 . 10233 mol of SO 2 will dissolve in 6 . 6 L of water to form a solution that is 4 . 10233 mol 6 . 6 L = 0 . 621566 M in H 2 SO 4 . 003 (part 3 of 4) 10.0 points What mass of SO 2 is produced in the burning of 1 tonne (1 t = 1000 kg) of highsulfur coal, if the coal is 4% pyrite by mass? Correct answer: 42 . 7181 kg. Explanation: m coal = 1000 kg m FeS 2 = 4%(1000 kg) = 40 kg = 40000 g MW FeS 2 = 55 . 845 g / mol + 2(32 . 065 g / mol) = 119 . 975 g MW SO 2 = 32 . 065 g / mol + 2(15 . 9994 g / mol) = 64 . 0638 g m SO 2 = 1000 kg coal parenleftbigg 40000 g FeS 2 1000 kg coal parenrightbigg parenleftbigg 1 mol FeS 2 119 . 975 g FeS 2 parenrightbigg parenleftbigg 8 mol SO 2 4 mol FeS 2 parenrightbiggparenleftbigg 64 . 0638 g SO 2 1 mol SO 2 parenrightbigg = 42718 . 1 g = 42 . 7181 kg SO 2 . nanni (arn437) HW 03 Mixtures and Kinetic Theory vanden bout (50985) 2 004 (part 4 of 4) 10.0 points From the previous problem, what is the vol ume of the SO 2 gas at 1 atm and 44 C? Correct answer: 17345 . 6 L....
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 Fall '07
 Fakhreddine/Lyon

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