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Unformatted text preview: CHBE 241 Material and Energy Balances Department of Chemical and Biological Engineering The University of British Columbia Final Examination (3 hours) Monday, 10 December 2007 Answer all 6 questions. Present all your calculations! 1. (5%) A suspension of calcium carbonate particles in water flows through a pipe. Your as- signment is to determine both the flow rate and the composition of this suspension. You proceed to collect the stream in a graduated cylinder for 1 min; you then weigh the cylinder, evaporate the collected water, and reweigh the cylinder. The following results are obtained: Mass of empty cylinder: 65 g Mass of cylinder + collected suspension: 565 g Volume collected: 455 mL Mass of cylinder after evaporation: 215 g. Calculate: (a) The volumetric flow rate and mass flow rate of the suspension. (b) The density of the suspension. (c) The mass fraction of calcium carbonate in the suspension. 2. (20%) According to http://www.mayoclinic.com/health/caffeine/AN01211, a 12 oz cup of Starbucks Tazo Chai Tea Latte contains 75 mg caffeine. If caffeine is eliminated from the body at a rate of dm c , sys / dt =- . 15 m c , sys , how long it will take for the caffeine in your...
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This note was uploaded on 04/05/2010 for the course CHEBE 241 taught by Professor Ali during the Winter '08 term at The University of British Columbia.
- Winter '08