HW02-solutions - kamalska(mk23835 HW02 Quigley(104001 This print-out should have 30 questions Multiple-choice questions may continue on the next column

HW02-solutions - kamalska(mk23835 HW02 Quigley(104001 This...

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kamalska (mk23835) – HW02 – Quigley – (104001) 1 This print-out should have 30 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. 001 10.0 points What is the maximum possible value of thevan’t Hoff factor for a solution of the strongelectrolyte FeCl3that is so dilute that no ionassociation occur? 002 (part 1 of 3) 10.0 points For the next three questions, consider thefollowing pressure diagram for a binary liquidcontaining A and B.01xA90 torr60 torrIf 1760 g of A (110 g/mol) and 1995 g ofB (105 g/mol) are mixed, what is the vaporpressure of B?1.90 torr2.27 torrcorrect3.60 torr4.48 torr5.76 torrExplanation: 4. 90 torr 5. 60 torr Explanation:
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2What is the corresponding total vapor pres-sure? 2. 60 torr 3. 48 torr 4. 76 torr correct 5. 27 torr Explanation: 0 1 0 . 46 60 torr 76 torr 005 10.0 points Chemical processes, like dissolving solids, are favored by (decreased, increased) potential energy and (decreased, increased, unchanged) disorder. 1. increased; increased 2. decreased; decreased 3. increased; decreased 4. 10.0 points A well-behaved (non-volatile, non-ionic) so- lute is dissolved in water to yield a solution that freezes at - 0 . 930 C. At what temper- ature would this solution boil under 1.0000 atm pressure? Note that K f = 1 . 86 C/ m , K b = 0 . 512 C /m . 1. 99.744 C 2. 101.394 C 3. 100.930 C 4. 100.256 C correct 5. 100.000 C 6. 99.070 C Explanation: T f = - 0 . 9306 C K f = 1 . 866 C /m K b = 0 . 512 C /m First, we have to determine the molality of this solution. Knowing the freezing point will lead us to the molality. Using the equation Δ T f = K f m and knowing that the freezing point of water is 0 C, we know that the freezing point has been depressed 0.930 C. This means the molality of this solution is 0 . 930 C = (1 . 86 C /m )( m ) m = 0 . 500 m
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  • Fall '08
  • QUIGLEY
  • Solubility, Vapor pressure, Freezing-point depression

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