PASCO CI-6729 (1X) CONDUCTIVITY SENSOR - Manual (Page 15)

11
012–06485B Conductivity Sensor
Experiment 2: Concentration Dependence of Conductivity in
Aqueous Solutions
Purpose
The purpose of this experiment is to explore the relationship between concentration and conductivity
in aqueous solutions.
Materials and Equipment Needed
• Conductivity Sensor • 150 ml distilled or deionized H
2
O
• Science Workshop version 2.2.5 or higher • citric acid crystalline powder
• PASCO computer interface • stirring rod
• computer • 150 ml bottled drinking H
2
O
• 250 ml beaker (5) • wash bottle of distilled or deionized H
2
O
• Conductivity Sensor manual
Procedure
1. Soak the Conductivity Electrode in distilled or deionized H
2
O for 5–10 minutes.
2. Set up the Conductivity Sensor according to the procedure detailed on pages 6–7 of the
manual (select Digits display only). Select the 20k scale on the amplifier box. Calibration
is not needed for this experiment.
3. Make sure all water samples are at room temperature (i.e. same temperature).
4. In the Experiment Setup window, click Sampling Options, and select the Keyboard
check box. In the Parameter box, type Mass, and in the Units box, type grams.
5. Click the Graph display to make it active. Click the Horizontal Axis Input button
( ), and select Mass (grams).
6. Add 0.25 grams of citric acid into the distilled/deionized water. Stir the solution until the
crystals have dissolved.
7. Click REC to begin recording data. (The Keyboard Sampling window will open. Move the
window so you can see the other displays.) In the Keyboard Input box, type the number of
grams added (0.25 grams) to the solution for Entry #1 and click Enter.
8. Add citric acid in 0.25 gram increments for the first 2.0 grams. in the Keyboard Input box,
type in the total mass of citric acid added to the solution for each increment. (Make sure the
reading on the Digits display stabilizes first.)
9. After two grams have been added, increase the increments to 0.5 grams until 5.0 grams of
citric acid have been added to the solution. Then increase the increments to 1.0 gram until