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Unformatted text preview: dh2964 Homework 3 Walker (53970) 1 This print-out should have 37 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001 1.0 points The dominant source of ground level ozone in the U.S. is 1. lightning strikes. 2. the photochemical reactions of unburned hydrocarbons emitted from power plants us- ing fossil fuel sources. 3. volcanic emissions. 4. transport from the stratosphere. 5. photochemical decomposition of NO 2 from automobile exhausts to produce O atoms that react with O 2 molecules. correct Explanation: In the presence of sunlight, NO 2 NO + O O + O 2 O 3 002 1.0 points Protective ozone is in the (mesosphere, strato- sphere, troposphere), but ozone in the (meso- sphere, stratosphere, troposphere) is a pollu- tant. 1. stratosphere; mesosphere 2. stratosphere; troposphere correct 3. mesosphere; stratosphere 4. troposphere; stratosphere Explanation: 003 1.0 points Carbon has several isotopes, one of which, with a mass of 14 amu, is radioactive. This isotope has 1. 6 protons and 6 neutrons. 2. 7 protons and 7 neutrons. 3. 8 protons and 6 neutrons. 4. 6 protons and 7 neutrons. 5. 6 protons and 8 neutrons. correct Explanation: Carbon has an atomic number of 6 and therefore has 6 protons. If the atomic mass (the number of p + + the number of n ) is 14 amu then there are 14- 6 = 8 neutrons in 14 C. 004 1.0 points Which isotope has 35 protons, 35 electrons, and 46 neutrons? 1. 35 46 Pd 2. 81 46 Pd 3. 46 35 Br 4. 81 35 Br correct Explanation: The standard nuclide symbol takes the form of A Z E were E is the element symbol, A is the mass number (number p + + number n ), and Z is the atomic number (number p + ). An isotope with 35 protons ( p + ) and 46 neutrons ( n ) has an atomic number of 35 and a mass number of 35 p + + 46 n = 81 amu. Br has an atomic number of 35, so the isotope is 81 35 Br. 005 1.0 points How many neutrons are there in one atom of 48 22 Ti? 1. None of these 2. 22 3. 26 correct 4. 48 dh2964 Homework 3 Walker (53970) 2 5. 70 Explanation: The standard nuclide symbol takes the form A Z E, where E is the element symbol, A is the mass number (number of n + number of p + ) and Z is the atomic number (number of p + ). The atomic number for 48 22 Ti is 22, and its mass number is 48. 48 = p + + n = 22 + n n = 48- 22 = 26 neutrons 006 1.0 points The atomic number, which orders the ele- ments in the periodic table, has been identi- fied as ? of the atom. 1. the sum of the number of protons and neutrons in the nucleus 2. the number of protons in the nucleus correct 3. the number of neutrons in the nucleus 4. the number of electrons in the nucleus Explanation: The atomic number defines the atom and refers to the number of protons in the atom....
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This homework help was uploaded on 03/19/2008 for the course CH 304k taught by Professor Walker during the Spring '08 term at University of Texas at Austin.
- Spring '08