exp12_ld

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Unformatted text preview: Name TA Your name TA's name Lab Day and Time Room Room Day & Time CHEMISTRY 21L LEARNING DEVICE Intermolecular Forces For calculations, you must show all of your work and include appropriate units to receive full credit. Answers to the discussion questions should be in the form of complete sentences. EXPT. 12 1. How is the average kinetic energy of a substance related to its temperature? (2 pts)       2. Use the Maxwell-Boltzman distribution below to answer the following questions. a) Which energy level (E' or E'') represents molecules that have stronger intermolecular forces than the molecules represented by energy level E? Which have weaker intermolecular forces? Explain. (3 pts)       b) If the black line on the graph below represents the Maxwell-Boltzman distribution of kinetic energy for the molecules before evaporation, which line (blue or orange) represents the E' molecules after evaporation and which line represents the E" molecules after evaporation. Explain. (3 pts)       d) Which of these solvents (E' or E") would have a larger change in temperature as the solvent evaporates? Explain. (3 pts)       3. Complete the following table. [Hint: The NIST Web Book (http://webbook.nist.gov/chemistry/) is a good reference for this question. You can download structures of the molecules from the NIST site or draw the structures by downloading MDL® ISIS/Draw: Chemically Intelligent Drawing Package for free from http://www.mdli.com/downloads/isis.draw/isisdrawreg.html] (9 pts). Sample methanol ethanol 1-propanol heptane octane nonane 1-butanol sec-butanol tert-butanol Formula CH3OH                                                 H Structure H C H O H Molar Mass ∆ Hvap (g/mol) (kJ/mol) 32.04                                                 37.35                                                                                                 :: ...
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This note was uploaded on 06/10/2010 for the course CHEM 102L taught by Professor N/a during the Spring '07 term at UNC.

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