exam3answers - Gu, Phillip Exam 3 Due: Dec 5 2007, midnight...

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: Gu, Phillip Exam 3 Due: Dec 5 2007, midnight Inst: Brodbelt 1 This print-out should have 24 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. The due time is Central time. Brodbelt CH301 Exam 3 Fall 2007 Use of programmable calculators or cell phones is considered cheating and thus is pro- hibited. You may not leave the room for any reason. You may not start the exam after 7;15 pm. GOOD LUCK! 001 (part 1 of 1) 10 points Water molecules bind to each other mainly by 1. breaking an O H bond in neighboring water molecules. 2. electrons being paired between them. 3. ejecting electrons from oxygen. 4. oxygen lone pair interactions with hydro- gen atoms of a neighboring molecule. cor- rect Explanation: O + H + H - + H O H + - 002 (part 1 of 1) 10 points Given: 4HCl(g) + O 2 (g) 2H 2 O( ) + 2Cl 2 (g) H =- 202 . 4 kJ/mol rxn What is the expected energy change for the reaction of three moles of H 2 O and six moles of Cl 2 ? 1. 303.6 kJ correct 2.-67.5 kJ 3. 67.5 kJ 4. 1821 kJ 5.-303.6 kJ 6.-202.4 kJ 7.-607.2 kJ 8.-1821 kJ 9. 607.2 kJ 10. 202.4 kJ Explanation: The first equation needs to be multiplied by 1 2 in order to get the equation were interested in. Thus its H is multiplied by 1 2 as well. The second equation needs to be multiplied by two in order to get the equation were interested in. We also multiply its H by two. The third equation needs to be reversed, so the sign of its H should change. Then we add the equations to get the equa- tion were interested in. We also add the ad- justed H values to get the answer,- 1015 . 4 kJ/mol rxn. 003 (part 1 of 1) 10 points Propane (C 3 H 8 ) is burned in oxygen to pro- duce carbon dioxide and water. The heat of combustion of propane is -2012 kJ/mole. How much heat is given off when 3.0 mol C 3 H 8 are reacted with 10.0 mol O 2 ? 1. 7392 kJ 2. 4024 kJ correct 3. 2012 kJ 4. 916 kJ 5. 6036 kJ Gu, Phillip Exam 3 Due: Dec 5 2007, midnight Inst: Brodbelt 2 6. 5122 kJ 7. 672 kJ 8. 1555 kJ Explanation: 004 (part 1 of 1) 10 points The molecules in the reaction NH 3 (g) + 3F 2 (g) NF 3 (g) + 3HF(g) contain only single bonds. What is the heat evolved or absorbed per mole of NH 3 that reacts? These bond energy values might be useful: H-F 566 kJ/mol, F-F 158 kJ/mol, N-H 391 kJ/mol, N-F 272 kJ/mol. 1.- 566 kJ/mol 2.-289 kJ/mol 3. None of these 4.- 867 kJ/mol correct 5.- 1105 kJ/mol 6. +151 kJ/mol 7. +867 kJ/mol 8. +1105 kJ/mol Explanation: 3(391)+3(158)-3(272)-3(566) = -867 005 (part 1 of 1) 10 points Which statement about intermolecular forces in liquids is FALSE?...
View Full Document

Page1 / 8

exam3answers - Gu, Phillip Exam 3 Due: Dec 5 2007, midnight...

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