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Unformatted text preview: Version 182 Exam 3 T Th sutcliffe (50985) 1 This print-out should have 28 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001 10.0 points Which statement is FALSE about C 2 ? 1. It has four electrons in 2 p orbitals. 2. It would be expected to have a shorter bond length than C 2+ 2 . 3. It is paramagnetic. correct 4. It has a bond order of 2. Explanation: 002 10.0 points In the heteronuclear diatomic molecule OF, the antibonding molecular orbitals have 1. more fluorine-like atomic orbital charac- ter. 2. more oxygen-like atomic orbital charac- ter. correct 3. This molecule does not form any molecu- lar orbitals. 4. no electrons in them. Explanation: The bonding molecular orbitals reflect the more electronegative element F and the an- tibonding molecular orbitals reflect the less electronegative element O. 003 10.0 points How many and bonds are in the molecule below? C C H N b b H H 1. 7 , 1 2. 6 , 1 3. 6 , 2 4. 5 , 1 5. 5 , 2 correct Explanation: Sigma bonds are the first bond formed be- tween any two bonded atoms. Any subse- quent bond is a pi bond. 004 10.0 points NOTE: Balance using whole number coeffi- cients. The following reaction is important in the removal of sulfur dioxide, a major source of acid rain, from the smokestacks of coal burn- ing power plants. When the equation CaO + SO 2 + O 2 CaSO 4 is balanced, the coefficient of calcium oxide (commonly called lime) is 1. 2. correct 2. 4. 3. 1. 4. 3. Explanation: A balanced equation must have the same number of each kind of atom on both sides of the equation. We find the number of each kind of atom using equation coefficients and composition stoichiometry. For example, we find there are 8 O atoms on the product side: ?O atoms = 2 CaSO 4 4 O 1 CaSO 4 = 8 O The balanced equation is 2 CaO + 2 SO 2 + O 2 2 CaSO 4 and the coefficient of calcuim oxide is 2. Version 182 Exam 3 T Th sutcliffe (50985) 2 005 10.0 points Gas X has a larger value than Gas Y for the van der Waals constant a. This indicates that 1. the molecules of gas X have a higher velocity than do the molecules of gas Y. 2. the molecules of gas X repel other X molecules. 3. the molecules of X are larger than the molecules of Y. 4. the molecules of X have stronger inter- molecular attractions for each other than the molecules of Y have for each other. correct Explanation: 006 10.0 points ClF 3 is a T-shaped molecule; therefore the hybridization of the Cl is 1. dspf . 2. sp 3 . 3. sp 3 d 2 . 4. sp 3 d . correct 5. sp 2 . Explanation: 007 10.0 points A gaseous mixture made from 6.00 grams of oxygen gas and 9.00 grams of chlorine gas is placed in a 15.0 L vessel at 10.0 degrees Celsius. What is the total pressure in the vessel?...
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- Fall '07