An Exercise in Freezing Point Depression

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3. Evaluations and ConclusionsWhat do you think is the “best” deicer for Twin Cities streets and highways? Why?Base your answer on the information obtained in this Experiment and summarized in thetable in Question 2. Explain or justify your choice. If there is a consensus within yourgroup, the group may submit a single table and paragraph here. However, if your opiniondiffers from the group’s, you may decide to write a “dissenting” opinion. Write the nameof each contributor on all joint work.4. Other Important considerationsYour Table covers only part of the information that needs to be considered when selectinga deicer. List at least 3 other factors that should be a part of the decision.10-22
Name: _________________________________________ Date:___________________Partner(s): _________________________________________ TA: ____________________Part V: Group Poster Project on “Selecting the Best Deicer forMinnesota Roads”(100 points: All contributing group members receive the same grade.)Prepare a poster using poster board of standard size and thickness. (There will be a 10point deduction from your assigned grade for failure to use the designated poster board.)Poster board is available from the lab stockroom for about $1.00 per sheet. The postershould be understandable to someone who has studied Chapter 11 in Zumdahl.Use your answers to the post-lab questions, the questions below, and any otherinformation you have obtained to prepare your group’s poster. Your TA may request anoral report from each group in addition to or instead of the preparation of a poster.1. Look up the cost of each deicer in a chemical catalogue. Use the cheapest possibleprice, which will probably be for the largest quantity and the lowest purity. Theprices paid for very large quantities (thousands of tons), as would be needed by amunicipal or state highway department, would be considerably lower, but catalogprices will hopefully at least give a relative ranking. You might also look for priceson the Internet or in a chemical trade magazine. Cargill, a privately held Minnesotabased company, is a major supplier of deicers and does extensive research on them.(Companies often do not quote prices to the public but negotiate them directly withcustomers such as MNDOT who use very large amounts of a product.)For the poster, search the library and Internet for information about theenvironmental effects of deicer chemicals. You might visit the Web pages of varioushighway departments and also nature magazines. Reference any web materials byreporting both the complete address and the date you accessed the material.a) Which deicers are the least expensive in terms of cost per ton and cost perpound?b) Compare the deicers as mass of ice melted per dollar2. Economists sometimes talk about “hidden costs” - costs that do not show upimmediately, but that do ultimately add to the “price” of a deicer. For snowremoval, some of the obvious expenses (besides buying the deicer) are the payrollfor snowplow and truck drivers, fuel and maintenance for the trucks, etc.However, most of these costs will be similar for each deicer compound.Environmental damage during mining or production, pollution and any of theresulting environmental degradation are examples of hidden costs.3. Select the “best” deicer from those studied in this experiment and write a briefparagraph to support and explain your choice.4. Work in groups of 4 to 6 to prepare a poster which will name the “best” deicer forMinnesota roads and which uses all available information to support your decision.10-23
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An Exercise in Freezing Point Depression

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