Electrochem lab description voltaic_cell_virtual_lab_

advertisement
Name______________
Period________
Purpose:
The students will identify and construct different types of electrochemical cells.
Safety Considerations:
Safety is of utmost importance
Electricity can be very dangerous. Do not attempt this lab if you are prone to holding
wires in your mouth while standing in a bucket of water. Never use a computer while
swimming.
You should put on your virtual lab goggles.
Materials:
Volataic part of the lab:
http://www.kentchemistry.com/moviesfiles/Units/Redox/VoltaicCellEMF.htm
electrolysis part of the lab:
http://www.kentchemistry.com/moviesfiles/Units/Redox/voltaiccelll20.htm
Procedure:
Visit the website above.
1. Click on the Go button next to the number 1334
2. Construct a data table:
3. Include a column for the cathode, cathode solution, anode solution, anode, #
electrons moved per atom of anode metal, voltage, and cell notation
4. Create a galvanic cell using all of the combinations of metals and solutions. If no
electrons move, write N/A in your data table.
Return to the virtual library,
1. Click on the go button next to the number 1335.
2. Construct a data table for this experiment which has a column for each variable,
predicted amount of deposition, and starting and ending masses for each
electrode.
3. Choose a metal for the cathode and anode, voltage, current, time, and electrolyte.
4. Calculate the amount of deposited material on the anode (show all work) Place in
data table.
5. Click the on button in the experiment, and record the masses of the electrodes at
the end of the time selected.
6. Repeat the procedure for 3 other combinations of electrodes and electrolytes.
Clean up and turn the computer off.
Analysis Questions:
Experiment 1
1) Describe the differences between the two types of cells you used today.
2) What is an electrode potential? What does a negative potential indicate?
3) What is the purpose of the salt bridge? Why must it be connected to both
electrolyte solutions?
4) What combination resulted in the most active cell? Why?
5) What combinations result in a ‘dead cell’ where no reaction occurred? Explain
why no electrons were moved.
6) Re-order the electrodes you used based on reduction potential. Use Copper as
your standard.
7) Calculate the voltage that the first 3 voltaic cells you created would produce if the
molarity of the anode solution was .001M instead of 1.0 M
8) What would happen to the voltage if the mass of the electrodes were increased?
Explain.
9) Zinc and silver are used in a voltaic cell. Zinc is the anode and Silver is the
cathode. If the concentration of Zinc chloride is 1M, and the voltage across the
cell is 0.84 calculate:
a. The concentration of silver in the half cell.
b. The Ksp of silver chloride.
Experiment 2
1) Describe what current is and what factor it plays in electrolysis.
2) Is this experiment spontaneous, why or why not?
3) Describe voltage and its affect on the ability to perform electrolysis.
Download