Exam 1 Version A Key

Exam 1 Version A Key - Chemistry 1515, Midterm Exam #1,...

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Chemistry 1515, Midterm Exam #1, Version A February 2, 2011 This exam is closed book, notes, papers, etc. You may use a calculator. If you need a physical constant or unit conversion factor that is not provided, please ask. This exam must represent your own work. Put your answers on an orange scantron form. Useful Information R = 8.314 J/mol K = 0.0821 L atm/mol K N A = 6.022 x 10 23 mol -1 1 atm = 760 Torr
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CHEM 1515, Spring 2011 Midterm Exam #1, Version A Page 2 1. Which exam version do you have? 2. Liquid ammonia (boiling point = -33.4 ° C) can be used as a refrigerant and heat transfer fluid. How much energy is needed to heat 25.0 g of NH 3 ( l ) from -65.0 ° C to -12.0 ° C? Specific heat capacity, NH 3 ( l ) : 4.7 J/(g · K) Specific heat capacity, NH 3 ( g ): 2.2 J/(g · K) Heat of vaporization: 23.5 kJ/mol Molar mass, м : 17.0 g/mol A. 5.5 kJ B. 6.3 kJ C. 39 kJ D. 340 kJ E. 590 kJ 3. From the following list of aqueous solutions and water, select the one with the lowest freezing point. A. 0.75 m (NH 4 ) 3 PO 4 B. 1.0 m CaSO 4 C. 1.0 m LiClO 4 D. 1.5 m CH 3 OH, methyl alcohol E. pure water 4. Select the false statement from the options below: A. Gases with high boiling points tend to be more soluble in water than ones with low boiling points. B. The solubility of gases in water increases with increase in the pressure of the gas. C. The only intermolecular interactions that are important for helium dissolved in water are dispersion and dipole/induced-dipole. D. Ice is less dense than water. E. Water is called the “universal solvent” because it dissolves nonpolar and polar solutes well. 5. Consider the following statements: I. Polymers in solution exist as a random coil, the size of which is expressed by its radius of gyration. II. The radius of gyration of a linear polymer is usually orders of magnitude smaller than that polymer’s extended length. III. Polymer solutions increase in viscosity with increasing polymer chain length. IV. “Degree of polymerization” refers to the temperature at which the polymer will form. Select the correct answer below: A. All of the above statements are correct. B. Statement IV is incorrect. C. Statements II is incorrect. D. Statements II and III are incorrect. E. Statements I and IV are incorrect
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CHEM 1515, Spring 2011 Midterm Exam #1, Version A Page 3 6. A certain solid metallic element has a density 7.87 g/cm 3 and a molar mass of 55.85 g/mol. It crystallizes with a cubic unit cell, with an edge length of 286.7 pm. Calculate the number
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Exam 1 Version A Key - Chemistry 1515, Midterm Exam #1,...

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