Title: Electrolytes
Purpose: to classify compo9unds as electrolytes by testing their conductivity in aqueous solution.
Materials: Virtual ChemLab Environment
Procedure:
1. Start Virtual ChemLab
2. Enter the Laboratory by clicking on the door marked General Chemistry Laboratory
3. Click Guest to enter (you do NOT need a password)
4. Enter the Titrations Laboratory, the third lab table from the right.
5. Click on the Stockroom window in the upper right of the screen.
Testing Solid Samples
6. Drag a bottle of NaCl, Na2CO3 (100%) and NaHCO3 (100%) to the spotlights on the Stockroom shelf and click the green Return to Lab arrow.
7. For each salt, complete the following procedure:
a. Drag the bottle to the spotlight next to the balance.
b. Click the drawer labeled Beakers and place a beaker in the spotlight next to the salt bottle.
c. Click on the Balance to zoom in and open the bottle by clicking on the lid.
d. Pick up the Scoop and scoop up some salt by dragging the scoop to the bottle and then down the face of the bottle. Pick up the largest sample possible and place it in the beaker. Click on the green Zoom Out arrow.
e. Move the beaker to the stir plate, underneath the buret.
f. Pick up the 25 mL graduated cylinder near the sink and hold it under the water tap until it fills.
g. Pour the water into the beaker by dragging the cylinder to the beaker.
h. Turn on the conductivity meter, which is on the far right corner of the lab table, and place the conductivity meter probe into the beaker.
i. Record the conductivity in the Data Table below.
j. Remove the probe, place the beaker in the red disposal bucket, and drag the salt bottle back to the Stockroom counter.
k. Repeat with the other two reagents.
8. When you have completed the three reagents, return to the Stockroom and drag the reagent bottles back to their places on the shelf.
9. Obtain three more samples KNO3, NH4Cl, Na2SO3, click the green Return to Lab arrow, and test the conductivity of these samples using the same procedure (# 7).
10. Click the red disposal bucket to clear the lab.
Testing Liquid Samples
1. Obtain solutions NH3, HCl, and HCN solutions by dragging them to the Stockroom shelf and then clicking the green Return to Lab arrow.
2. For each salt, complete the following procedure.
a. Place a beaker on the spotlight to the left of the stir plate.
b. Click on the drawer labeled PIPETS and drag a 25 mL pipet and attach it to the left side of the metal stand
c. Pick up the bottle of NH3 solution from the Stockroom shelf and pour into the beaker until the beaker is at least one-quarter full.
d. Click the pipet bulb (Fill Pipet) to fill the pipet.
e. Place the used beaker in the red disposal bucket.
f. Drag a new beaker to the spotlight under the pipet and click the pipet bulb to Empty Pipet.
g. Drag the beaker to the stir plate.
h. place the conductivity meter probe into the beaker and record the conductivity in the Data Table below.
i. Repeat with the other 2 solutions.
3. Click the red disposal bucket to completely clear the lab.
Results: Record the conductivity values in the following data table:
Conductivity
Electrolyte Behavior
(yes/no)
Type of Compound
(ionic/covalent)
Discussion:
1. Summarize what you did.
2. Explain why you used different procedures for solid and liquid samples.
3. Would any of these compounds conduct electricity in the solid form? Explain.
Conclusion: Relate electrolyte behavior and compound type.
Reflection: Commentary about what you learned about electrolytes in this lab simulation.
Save a copy of this lab writeup in your folder and in your Virtual Lab NB Folder on the Shared Folder. (You may email this lab writeup to and I will save it in your Virtual Lab NB)
Print out a copy of this lab and tape it into your Lab NB!
Judith Nuño Chemistry 2006/2006