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Unformatted text preview: Version 265 Exam 1 mccord (51600) 1 This printout should have 34 questions. Multiplechoice questions may continue on the next column or page find all choices before answering. 001 10.0 points Which response identifies a possible for the lastfilled electron in a chloride ion? 1. 3 , 1 , 1 correct 2. 2 , , 1 3. 2 , 1 , 2 4. 3 , 3 , 1 5. 2 , , 6. 3 , , Explanation: The are written in format n,,m . The electronic configuration for the chloride ion is [Ne] 3 s 2 3 p 6 , so the lastfilled electron is in 3 p . For the 3 p orbital, n = 3, = 1, and m can be 1 , , +1. (The m can be any of those values because the orbitals are degenerate, so may fill in any order.) 002 10.0 points Carbon emits photons at 745 nm when ex posed to blackbody radiation. How much energy would be obtained if 44 g of carbon were irradiated? 1. 5 . 90 10 5 J correct 2. 7 . 08 10 6 J 3. 7 . 08 10 3 J 4. 1 . 17 10 17 J 5. 9 . 11 10 21 J 6. 2 . 67 10 19 J Explanation: = 745 nm = 7 . 45 10 7 m m C = 44 g Assume each carbon atom emits one pho ton. For each photon E 1 = h = h c = (6 . 626 10 34 J s) (3 10 8 m / s) 7 . 45 10 7 m = 2 . 66819 10 19 J , so the total energy emitted is E = E 1 n = 2 . 66819 10 19 J C atom 6 . 022 10 23 C atoms 1 mol C atoms 1 mol C atoms 12 . 01 g C (44 g C) = 5 . 88663 10 5 J . 003 10.0 points How many electrons can possess this set of quantum numbers: principal quantum num ber n = 4, angular quantum number = 2? 1. 14 2. 6 3. 4. 4 5. 12 6. 16 7. 10 correct 8. 8 9. 18 10. 2 Explanation: Use the rules for the quantum numbers: If n = 4 and = 2 ( i.e. , 4 d ), then m = 2 , 1 , , +1 , +2 are permitted; there are five different orbitals and m s = 1 2 , each holding two electrons. Version 265 Exam 1 mccord (51600) 2 004 10.0 points 2 (2 , 1 , 0) represents which orbital? 1. Different orbitals, depending on the ele ment in question. 2. The probability of a 2 p orbital becoming a 1 s orbital. 3. 2p orbital. correct 4. 2s orbital. Explanation: 2 (2 , 1 , 0) gives the probability of finding an electron in an orbital with quantum num bers 2,1,0, which corresponds to n=2, l=1, and ml=0. That is one of the 2p orbitals. 005 10.0 points For the reaction ? C 6 H 6 + ? O 2 ? CO 2 + ? H 2 O 45 . 6 grams of C 6 H 6 are mixed with 159 . 7 grams of O 2 and allowed to react. How much CO 2 could be produced by this reaction? 1. 205 . 1 g 2. 123 . 4 g 3. 323 . 8 g 4. 135 . 3 g 5. 239 g 6. 110 . 1 g 7. 291 . 4 g 8. 192 . 8 g 9. 154 . 2 g correct 10. 175 . 8 g Explanation: m C 6 H 6 = 45 . 6 g m O 2 = 159 . 7 g The balanced equation is 2 C 6 H 6 + 15 O 2 12 CO 2 + 6 H 2 O ....
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This note was uploaded on 05/02/2011 for the course CHEM 301 taught by Professor Wandelt during the Spring '08 term at University of Texas at Austin.
 Spring '08
 wandelt
 Electron

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