DRAFT: This module has unpublished changes.

Equipment

  • Data collection system
  • Red tide machine
  • Sensor extension cable
  • Three cuvettess
  • Three 50 mL Beakers
  • Three 5 mL syringes
  • 4 inch watch glass
  • 20 mL 0.1 M NaOH
  • 20 mL 1.2 x 10^-5 M crystal violet
  • 30 mL of deionized water
  • Marking pen
  • Kim wipes

Procedure

  1.  Start a new experiment on the data collection system.
  2.  Connect the red tide to the GLX and set up the parameters for the experiment on the GLX.
  3.  Put about 10 mL of crystal violet, NaOH and deionized water each in its own 50 mL beaker. Make sure to cover the NaOH with a watch glass to minimize the change of it reacting with carbon dioxide.
  4.  Label each of the beakers and then label the three syringes with either crystal violet, NaOH or water.
  5.  For the first trial refer to the table of volumes of liquids to determine what volume of each liquid to get in the syringe

Table 1: Initial Volumes and Concentrations

Trial Initial Concentration (M) Initial Concentration (M) Volume (mL) Volume (mL) Volume (mL) Volume (mL)
  [CV+] [OH-] Crystal Violet 1.2x10^-5 M NaOH 0.10 M Water Total
1 4.8x10^-6 2.5x10-2 1.20 0.30 1.50 3.00
2 9.6x10^-6 5.0x10^-2 2.40 0.60 0.0 3.00
3 9.6X10^-6 2.5x10-2 2.40 0.30 0.30 3.00

 

6.  Get rid of the air bubbles from the syringes by holding the syringe over the sink , pointing upward, and knocking gently on the syringe and pushing the plunger in until all the air is expelled. Draw in more solution as needed.

 

7.   For trial one obtain the correct volumes for water and NaOH and put them in a cuvette.

 

8.  As quickly as possible add the correct volume of crystal violet for trial 1 into the cuvette, put parafilm over the cuvette and then invert it a few times. Make sure the cuvette is clean by cleaning it with kim wipes.

 

9. Place the cuvette in the red tide and press play on the GLX to start recording data.

 

10. Record data for about 5 minutes.

 

11. Repeat steps 5-10 for the other two trials.

 

12.  In the data collection system create a calculated data set to obtain the concentrations as a function of time for each trial using Beer's Law knowing that the path l= 1.65 and E- 5x10^4 M^-1s^-1.

 

13. Display the data set on the y-axis and time on the x-axis.

 

14. Find the slope and y intercept of the best fit line.

 

15. Make sure the lab station is cleaned.

DRAFT: This module has unpublished changes.