Lab 10 part 2

Lab 10 part 2 - How Minnesotans Clear the Streets in...

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How Minnesotans Clear the Streets in Winter: An Exercise in Freezing Point Depression Part II Data: 9/20/2011 Course Number: CHEM1022 Experimenter: Hongbai Li Lab Partner: Sarah, Birra, Patrick
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Reference: Chemistry 1022 Lab Manual, 2 nd Edition 10-6~10-10 Purpose The purpose of this experiment is to determine the corrosivity, the enthalpy of solutions, ∆H soln , over a range of concentrations as well as plot the freezing curve for water. Procedure: Part IB: 1. Take two iron nails. Remove any rust with sandpaper or steel wool. 2. In a small labeled beaker, place 2.0 g of deicer in 20 mL of water. Put one nail in it and the other one in 20 mL of DI water. Lean each nail against the side of the beaker in order to stick part of it out into the air. 3. After approximately 30 minutes, after an hour, and also at the end of the lab period, examine the nail carefully. Record a brief description of the observations along with a rating. 4. Leave the beakers in the drawer covered with a watch glass. Part IIA: 1. Measure 10 mL of water into a calorimeter well by using a small graduated cylinder. Record the exact volume. Suspend a calibrated temperature sensor in the water. 2. Weigh the indicated amount of salt in a small, clean, dry beaker and record its mass. 3. Rinse the well thoroughly with DI water and repeat the procedure. 4. Calculate the enthalpy of solution in J/g and kJ/mol. Part IIB: 1. Add a sample of DI water which is several degrees above its freezing point. 2. Immerse the test tube in a beaker containing an ice/water/low grade NaCl mixture and plot temperature as a function of time until the temperature is clearly below the freezing point of water. 3. Continue to collect data until the temperature levels off to obtain the entire freezing curve. Results:
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Lab 10 part 2 - How Minnesotans Clear the Streets in...

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