User:Michael Corrado/Notebook/Experimental Chemistry Fall 2016/2016/09/02

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Objective

  1. Test the accuracy of pipettes
  2. Measure the ion conductivity of various purity grades of water
  3. Prepare an NaCl solution and a dye solution
  4. Prepare stock solutions
  5. Prepare three PVOH (Polyvinyl Alcohol) films

Procedure

  1. Testing Pipettes
    • As shown below in Table 1, four different pipettes (P5000, P1000, P200, and P20) were tested for accuracy by comparing the actual and theoretical masses of different volumes of water. From these results, a percent error was calculated.
  2. Measuring the conductivity of water
    • As shown in Table 2 below, the ion conductivity and purity of Tap water, DI water, HPLC water, and LCMS water were measured using a conductivity and pH meter.
  3. Preparation of NaCl and dye solutions
    • In order to prepare 100 mL of 1.71 mM NaCl solution, 0.0010 g of NaCl was added to 100 mL of water.
    • In order to prepare 10 mL of μM dye, 277.5 μL of dye was added to a 10 mL flask.
  4. Preparation of stock solutions
    • A 100 mL 200 ppm Malachite Green stock solution was prepared by adding 20 mg of Malachite Green powder to 100 mL of water.
    • 100 mL of a 3% wt Bentonite solution was prepared by dissolving 3 g of Bentonite in 100 mL of water.
    • The next stock solution was prepared by creating a solution of 40 g Na2SO4, 4 mL H2SO4 (conc.), and 200 mL water.
    • 250 mL of a 1.0 M HCl solution was prepared from a 12.1 M concentrated HCl solution via dilution. 20.67 mL of the concentrated solution was added to water to make the stock solution.
    • 250 mL of a 0.2 M sodium bicarbonate solution was prepared by dissolving 4.2 g of sodium bicarbonate in water.
  5. Preparation of PVOH films
    • Three separate beakers of 12 mL of water and 1.0 g PVOH were placed on a hot plate and stirred until the PVOH crystals had dissolved.
    • Then, 0.5 mL of glutaraldehyde were added to the first beaker, 0.5 mL of glutaraldehyde and 1.0 g of Bentonite were added to the second beaker, and 1.0 ml of glutaraldehyde were added to the third beaker.
    • after everything had dissolved inside the beakers, the films were transferred to three labeled teflon dishes and left under a fume hood to form.

Data

  1. Table 1: Accuracy of pipettes

JML Experimental Feb2 Table1.png

  • Based on the average of percent error, the least accurate pipette was the P1000 and the most accurate pipette was the P5000. The most precise pipette was the P200.

JML Experimental Feb2 Table2.png

  • Based on the ion conductivity of the water samples, the least pure was tap water and the most pure was DI water.