hw3ans - wilson (tw8656) H03: Mixtures and KMT mccord...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: wilson (tw8656) H03: Mixtures and KMT mccord (50960) 1 This print-out should have 19 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. All students from Dr. McCords MWF 11am class (50960) must report to the correct room for the exams. There are 2 different rooms and the class is split according to the first letter of your last name. Go to the right room or you WILL receive a zero on the exams. A-L go to UTC 2.112A M-Z go to UTC 2.102A 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 77 L of oxygen at 3 . 58 atm and 149 C with an excess of iron pyrite? Correct answer: 231 . 121 g. Explanation: P = 3 . 58 atm T = 149 C + 273 = 422 K R = 0 . 08206 L atm K mol V = 77 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 . 58 atm) (77 L) ( . 08206 L atm K mol ) (422 K) = 7 . 96031 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 (7 . 96031 mol O 2 ) = 231 . 121 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 5 . 5 L of aqueous solu- tion, what is the molar concentration of the resulting sulfurous acid (H 2 SO 3 ) solution? Correct answer: 1 . 0526 M. Explanation: V = 5 . 5 L SO 2 (g) + H 2 O( )- H 2 SO 3 (aq) . From the stoichiometry, n SO 2 = (7 . 96031 mol) parenleftbigg 8 n SO 2 11 n O 2 parenrightbigg = 5 . 78931 mol . 5 . 78931 mol of SO 2 will dissolve in 5 . 5 L of water to form a solution that is 5 . 78931 mol 5 . 5 L = 1 . 0526 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 high-sulfur 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 wilson (tw8656) H03: Mixtures and KMT mccord (50960) 2 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 ....
View Full Document

This note was uploaded on 09/26/2011 for the course CH 301 taught by Professor Fakhreddine/lyon during the Fall '07 term at University of Texas at Austin.

Page1 / 7

hw3ans - wilson (tw8656) H03: Mixtures and KMT mccord...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online