Name: __________________________________ Period: ______ Date: __________________________
Conductivity of Ionic and Covalent Compounds
If an ionic compound is dissolved in water, it dissociates into ions and the resulting solution will conduct
electricity. Dissolving solid Sodium Chloride in water releases ions according to the equation:
NaCl (s) + H2O (l)  Na+ (aq) +Cl- (aq)
In this experiment you will investigate the conductivity of Ionic Compounds versus Covalent Compounds. You
will investigate these properties using a Conductivity Probe. Conductivity will be measured as concentration of
the solution is gradually increased by the addition of drops of NaCl solution (concentration of this solution is
1.0 M). The same procedure will be used to investigate the effect of Covalent Compound Solutions with the
same concentration as well as two unknown solutions. The first Covalent Compound Solution you will test will
be Sucrose, Table Sugar, C12H22O11. Of the two unknown soultions, one will be an Ionic Compound Solution
and the other will be a Covalent Compound Solution.
When the probe is placed in a solution that contains ions, and thus has the ability to conduct electricity, an
electrical circuit is completed across the electrodes that are located on either side of the hole near the bottom of
the probe body (see Figure 1), and this produces a conductivity reason. The unit of conductivity used in this
experiment is the microsiemens per centimeter or µS/cm.
You will first measure the conductivity of distilled water, and then you will measure to conductivity of the NaCl
solutions and C12H22O11 solutions. Finally, you will measure two unknown solutions to determine whether they
are Ionic Compound Solutions or Covalent Compound Solutions.
Materials
LabQuest Unit and Conductivity Probe
100mL Glass Beaker
100 mL Plastic Beaker
Distilled Water
Wash bottles
Electronic Scale
100 mL Graduated Cylinder
1.0 M NaCl solution
1.0 M C12H22O11 solution
1.0 M Isopropyl Alcohol solution
1.0 M CaCl2 solution
Plastic Pipette
Watch Glass
Paper Towels
Procedure
Part 1: Sodium Chloride
1. Place the Watch Glass on the Electronic Scale and zero the scale
2. Measure 2.9 grams of NaCl and place in 100 mL Glass Beaker
3. Measure 50mL of distilled water using the Graduated Cylinder and place in 100 mL Glass Beaker.
4. Stir the NaCl and Distilled Water Solution
5. Measure 75 mL of distilled water using the Graduated Cylinder and place in 100 mL Plastic Beaker
6. Plug the Conductivity Probe into the LabQuest Unit
7. Place the Conductivity Probe into the center of the 100 mL Plastic Beaker and hold steady.
8. Press the Red Box on the LabQuest Unit screen and click “Zero”
9. Record the Value shown onto Data Table 1.
10. Using the Pipette place one drop of NaCl solution into the 100 mL Plastic Beaker and stir with the
probe.
11. Place the Conductivity Probe back in the center of the 100 mL Plastic Beaker and record the new value
onto Data Table 1.
12. Repeat steps 10-11 until Conductivity Values are found for drops 2-5.
13. Dump all solutions in the sink and wash thoroughly all plastic/glassware.
Part 2: Sucrose
1. Place the Watch Glass on the Electronic Scale and zero the scale
2. Measure 17.1 grams of Sucrose and place in 100 mL Glass Beaker
3. Measure 50mL of distilled water using the Graduated Cylinder and place in 100 mL Glass Beaker.
4. Stir the Sucrose and Distilled Water Solution
5. Measure 75 mL of distilled water using the Graduated Cylinder and place in 100 mL Plastic Beaker
6. Plug the Conductivity Probe into the LabQuest Unit
7. Place the Conductivity Probe into the center of the 100 mL Plastic Beaker and hold steady.
8. Press the Red Box on the LabQuest Unit screen and click “Zero”
9. Record the Value shown onto Data Table 2.
10. Using the Pipette place one drop of Sucrose solution into the 100 mL Plastic Beaker and stir with the
probe.
11. Place the Conductivity Probe back in the center of the 100 mL Plastic Beaker and record the new value
onto Data Table 2.
12. Repeat steps 10-11 until Conductivity Values are found for drops 2-5.
13. Dump all solutions in the sink and wash thoroughly all plastic/glassware.
Part 3: Unknown Solutions
1.
2.
3.
4.
5.
6.
7.
Obtain 50 mL of Unknown Solution 1 from teacher
Measure 75 mL of distilled water using the Graduated Cylinder and place in 100 mL Plastic Beaker
Plug the Conductivity Probe into the LabQuest Unit
Place the Conductivity Probe into the center of the 100 mL Plastic Beaker and hold steady.
Press the Red Box on the LabQuest Unit screen and click “Zero”
Record the Value shown onto the Data Table
Using the Pipette place one drop of Unknown Solution 1 into the 100 mL Plastic Beaker and stir with
the probe.
8. Place the Conductivity Probe back in the center of the 100 mL Plastic Beaker and record the new value
onto the Data Table
9. Repeat steps 7-8 until Conductivity Values are found for drops 2-5.
10. Dump all solutions in the sink and wash thoroughly all plastic/glassware.
11. Repeat Steps 1-10 for Unknown Solution 2.
Results
Data Table
Solution
0 Drops
1 Drop
2 Drops
3 Drops
4 Drops
5 Drops
Conductivity of
NaCl (µS/cm)
Conductivity of
C12H22O11 (µS/cm)
Conductivity of
Unknown #1
(µS/cm)
Conductivity of
Unknown #2
(µS/cm)
Analysis and Interpretation Questions:
1. For the first two solutions, the NaCl Solution and the C12H22O11 Solution, which Solution contains Ionic
Compound and which Solution contains Covalent Compounds? How do you know?
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
2. One of the Unknown Solutions was C₃H₇OH, Isopropyl Alcohol. What type of Compound is this, Ionic
or Covalent? How do you know?
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
3. The other Unknown Solution was CaCl2, Calcium Chloride. What type of Compound is this, Ionic or
Covalent? How do you know?
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
4. Identify Unknown Solution #1 and explain how you came to this conclusion. Refer to the information
obtained during this Laboratory Procedure.
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
5. Identify Unknown Solution #2 and explain how you came to this conclusion. Refer to the information
obtained during this Laboratory Procedure.
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________
____________________________________________________________________________________