solution2_pdf

solution2_pdf - Version 130 Homework 2 Lyon(53565 This...

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Version 130 – Homework 2 – Lyon – (53565) 1 This print-out should have 15 questions. Multiple-choice questions may continue on the next column or page – fnd all choices beFore answering. This homework assignment is due Wednes- day, January 30, by 4:00PM. 001 10.0 points Which oF the Following statements is true re- garding solubility? Assume the solute does not a±ect the solvent and we are dealing with dilute solutions. 1. We can expect substances with positive enthalpies oF solution always to be soluble only iF the entropy oF solution is positive. 2. We can expect substances with negative enthalpies oF solution always to be soluble. correct 3. We can expect substances with positive enthalpies oF solution always to be soluble only iF the entropy oF solution is negative. 4. All the statements are False because the solute always a±ects the solvent resulting in a negative entropy oF solution. 5. We can expect substances with positive enthalpies oF solution always to be soluble. Explanation: 002 10.0 points What is the molality oF sodium perchlorate (NaClO 4 ) in a solution preparted by dissolv- ing 125 g sodium perchlorate monohydrate in 500.0 g water? 1. 0.900 m 2. 2.04 m 3. 3.56 m 4. 0.250 m 5. 1.78 m correct Explanation: 003 10.0 points Calculate the molality oF ethanol in a solution oF water, iF the mole Fraction oF ethanol is 0.300. 1. 64.3 m 2. 45.2 m 3. 53.5 m 4. 23.8 m correct 5. 34.6 m Explanation: 004 10.0 points Aqueous ammonia (approx 28% by weight) is 15.0 M and has a density oF 0.90 g/mL. Calculate the molality oF ammonia in this solution. 1. 15.4 m 2. 37.3 m 3. 42.6 m 4. 23.3 m correct 5. 49.1 m Explanation: 005 10.0 points Which oF the Following 1.0 M solutions con- tains the most particles? 1. ethylene glycol 2. potassium chloride 3. magnesium sulFate 4. sodium sulFate correct 5. glucose

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Version 130 – Homework 2 – Lyon – (53565) 2 Explanation: 006 10.0 points For gases that do not react chemically with water, the solubility of the gas in water gen- erally (decreases, increases) with an increase in the pressure of the gas and (decreases, in- creases) with increasing temperature. 1. decreases; decreases 2. increases; increases 3. decreases; increases 4. increases; decreases correct Explanation: An increase in pressure means that you have increased the concentration of gas above the solvent surface, thereby increasing the concentration of the gas in the solvent. In- creasing the temperature will decrease the
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This note was uploaded on 07/15/2008 for the course CHE 302 taught by Professor Davidvandenbout during the Spring '08 term at University of Texas.

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solution2_pdf - Version 130 Homework 2 Lyon(53565 This...

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