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Unformatted text preview: Chemistry 131 – Preliminary Exam I 1 October 2009 8:00 a.m. to 9:30 a.m. Name: ________________________ Workshop Meeting Time (day/hour and building) ________________________ (2 pts. Extra credit) ID #: ________________________ This exam consists of six (6) questions, one extra credit problem, and a page of potentially useful information. Please check BEFORE you begin to make sure that you have a complete exam. Please do all your work on the pages provided. You may use the backside of pages for additional work, but please tell us that you are doing so (i.e. an arrow with a note in clear English saying "more work on back"). SHOW ALL WORK . GIVE UNITS for all answers that require them. Partial credit can only be given for those answers for which work is provided. CIRCLE YOUR ANSWER. We ask this so that we don't have to interpret what you intended as your final answer. GOOD LUCK! Prob. W.S. 1(30) 2(25) 3(30) 4(25) 5(30) 6(25) E.C.(5) Total 165 Score ROCHESTER U N I V E R S I T Y O F University of Rochester Rochester, New York 14627-0216 COLLEGE OF ARTS AND SCIENCE DEPARTMENT OF CHEMISTRY 1) Note: these problems can be solved with little calculation. Showing work is not required. Consider the following four samples: 1 mol of Iron (III) Oxide 32.00 g of molecular oxygen 5.0 g of Cesium Phosphate 0.5 mol of Carbon Dioxide a) (5 pts.) Write the molecular formula for the sample that has the least number of oxygen atoms. b) (5 pts.) Write the molecular formula for the sample that has the most total atoms. c) (5 pts.) Write the molecular formula for the sample that has the largest mass. 1d) Consider the following four solutions all with a volume of 100 mL: 100 mL of 1.0 M NH 4 OH 300 mL of 0.5 M NaCN 200 mL of 1.5 M K 2 CrO 4 200 mL of 0.5 M K 2 Cr 2 O 7 (5 pts.) Write the chemical name in the space below for the sample that has the lowest concentration of cations....
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This note was uploaded on 03/23/2011 for the course CHM 131 taught by Professor Krugh during the Fall '04 term at Rochester.
- Fall '04