CH 301 - Thomas Phillip – Exam 1 – Due Oct 4 2007 11:00 pm – Inst Brodbelt 1 This print-out should have 27 questions Multiple-choice

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Unformatted text preview: Thomas, Phillip – Exam 1 – Due: Oct 4 2007, 11:00 pm – Inst: Brodbelt 1 This print-out should have 27 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 1 October 3, 2007 Programmable calculators and cell phones are prohibited. You may not leave the room until you turn in your exam. GOOD LUCK! 001 (part 1 of 1) 10 points Consider the reaction: N 2 + 3H 2 → 2NH 3 What is the percent yield if 45.5 grams of NH 3 is produced upon reaction of 13.0 moles N 2 and 29.0 moles H 2 ? 1. 10 . 3% 2. 20 . 6% 3. 27 . 6% 4. 35 . 4% 5. 13 . 8% correct 6. 6 . 14% Explanation: ? g NH 3 = 13 . 0 mol N 2 × µ 2 mol NH 3 1 mol N 2 ¶ × µ 17 . 03 g NH 3 1 mol NH 3 ¶ = 442 . 78 g NH 3 ? g NH 3 = 29 . 0 mol H 2 × µ 2 mol NH 3 3 mol H 2 ¶ × µ 17 . 03 g NH 3 1 mol NH 3 ¶ = 329 . 247 g NH 3 H 2 is the limiting reagent. ? % yield NH 3 = 45 . 5 g NH 3 329 . 247 g NH 3 × 100% = 13 . 8194 % yield NH 3 002 (part 1 of 1) 10 points In an atom the maximum number of electrons having the quantum numbers n = 6 and ‘ = 3 is 1. 14. correct 2. 72. 3. 10. 4. 7. 5. 6. Explanation: 14 electrons can have this set of quantum numbers. Where ‘ = 3, seven values of m ‘ are possible, namely, 3, 2, 1, 0,- 1,- 2, and- 3. Each one of these m ‘ values represents a single orbital, so there are 7 orbitals. Since each orbital can accomodate 2 electrons, 14 electrons can have this set of n and ‘ values. 003 (part 1 of 1) 10 points An electron is confined to a one-dimensional box of length L. It falls from the second en- ergy level to the ground state, and releases a photon with a wavelength of 322 nm. What is the length of the box? 1. 0.303 nm. 2. 4.32 nm. 3. 2.92 nm. 4. 1.14 nm. 5. 322 nm. 6. 292 nm. Thomas, Phillip – Exam 1 – Due: Oct 4 2007, 11:00 pm – Inst: Brodbelt 2 7. 0.541 nm. correct 8. 1.61 nm. 9. 0.151 nm. Explanation: 004 (part 1 of 1) 10 points How many s electrons and p electrons does Mn possess? 1. 8 s , 12 p correct 2. 6 s , 6 p 3. 8 s , 18 p 4. 8 s , 6 p 5. 6 s , 18 p 6. 7 s , 13 p 7. 7 s , 18 p 8. 7 s , 12 p 9. 6 s , 12 p Explanation: The electron configuration for Mn is 1 s 2 2 s 2 2 p 6 3 s 2 3 p 6 4 s 2 3 d 5 2 + 2 + 2 + 2 = 8 s 6 + 6 = 12 p 005 (part 1 of 1) 10 points An electron is in the first quantum level in a box of length L. If the box is stretched so that the length doubles, what happens to the resulting energy of the electron? How would this influence the wavelength of a pho- ton needed to excite the electron to the second energy level? 1. energy of electron is decreased by a factor of two; wavelength of photon is decreased by a factor of two....
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This note was uploaded on 06/07/2011 for the course CH 301 taught by Professor Fakhreddine/lyon during the Fall '07 term at University of Texas at Austin.

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CH 301 - Thomas Phillip – Exam 1 – Due Oct 4 2007 11:00 pm – Inst Brodbelt 1 This print-out should have 27 questions Multiple-choice

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