Methods

1. Start a new experiment on the data collection system
2. Connect the colorimeter to the data collection system
3. Calibrate the colorimeter
4. Put about 20 mL of the crystal violet solution, the sodium hydroxide solution, and the distilled water in separate 50-mL beakers, label the beakers.
5. Cover the NaOH solution with a watch glass.
6. Label one syringe "CV", one "NaOH", and one "water"
7. For the first run, fill the three syringes with the volume of liquids specified below for trial 1:

1. Eliminate air bubbles from the syringes by holding the syringe over a sink, pointing upward, knocking gently on the syringe and pushing the plunger in until all the air is expelled.
2. Perform the experiment for each of the three runs as follows:

• Deliver the water and sodium hydroxide solutions from the syringe into a clean cuvette
• Start data collection system
• As quickly as possible, ass the crystal violet solution to the cuvette, close the cuvette, invert it a few times, wipe it dry and clean and place it into the colorimeter.
• Immediately close the lid on the colorimeter and start data recording
• Continue recording until the absorbance drops below 0.1
• Stop data recording and clean the cuvette
• For the next run, fill the three syringes with the volume of liquids specified for the next trial.

1. Clean up according to teachers instructions

Equipment

• Data collection system
• Colorimeter
• Sensor extension cable
• Cuvette
• Beaker (3), 50-mL
• Syringe (3), 5-mL
• Watch glass, 4 in
• 0.1 M Sodium hydroxide, 20 mL
• Water, deionized, 30 mL
• Marking pen
• Kim wipes