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Elbel, Brittany – Homework 3 – Due: Feb 6 2006, noon – Inst: J A Holcombe1Thisprint-outshouldhave22questions.Multiple-choice questions may continue onthe next column or page – find all choicesbefore answering.The due time is Centraltime.001(part 1 of 1) 10 pointsSeveralinterestingobservationsfromtheworld around you are listed below.Which of these is NOT explained by a col-ligative property?1.A lobster will die when placed in freshwater.2.Antifreeze is added to a car radiator tokeep the car from overheating.3.The freezing point of water is loweredwhen salt is added.4.Water boils at a higher temperature whensalt is added.5.At high altitude it takes longer to cookspaghetti.correctExplanation:Colligative properties of a solution dependon the number of solute particles in solution,not the type.Boiling point variations dueto pressure changes have nothing to do withsolutions and colligative properties (boilingpoint variations due to particles in solution,etc.).002(part 1 of 1) 10 pointsWhich of the following statements about col-ligativepropertiesofaqueoussolutionsisFALSE?1.The higher the concentration of solute inthe solution, the higher the vapor pressure ofthe solvent.correct2.Osmosis is a colligative property.3.For a given solution, the freezing pointwill be lowered more than the boiling pointwill be raised.4.Colligative properties only depend on thenumber of solute particles present in solu-tion.Explanation:Colligative properties, which include osmo-sis, vapor pressure lowering, melting and boil-ing point elevations, depend only on the num-ber of solute particles present in solution, noton their properties. The effect on the meltingpoint of a given solution is less than the effecton its boiling point.With a higher concentration of non-volatilesolute the concentration of the solvent in thesolution is lower, causing the vapor pressureof the solution to be lower.003(part 1 of 1) 10 pointsWhich of the following would likely dissolvein benzene?1.Ca(HCO3)22.NaCl3.Na2CO34.Cl2CCCl2correct5.C6H12O6Explanation:004(part 1 of 1) 10 pointsWhich of the following solutes is likely to bemost soluble in water?1.Br22.carbon tetrachloride (CCl4)3.CS24.ethanol (CH3CH2OH)correctExplanation:005(part 1 of 1) 10 pointsCalculate the number of moles of oxygen thatwill dissolve in 45 L of water at 20◦C if the par-
Elbel, Brittany – Homework 3 – Due: Feb 6 2006, noon – Inst: J A Holcombe2tial pressure of oxygen is 0.21 atm.Henry’sconstant for oxygen is 0.0013molL·atm.1.0.0013 mol2.0.00027 mol3.0.0062 mol4.0.012 molcorrect5.0.28 molExplanation:006(part 1 of 1) 10 pointsCalculate the molality of perchloric acid in 9.2M HClO4(aq). The density of this solution is1.54 g/mL.