experiment 17 electrochemical cells and thermodynamics che1181
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Experiment 17
Electrochemical Cells and Thermodynamics
CHE118 1
In Lab
• Work in groups of 2
• Each student does their own graph and calculations
CHE118 2
Modifications to Experiment
• The reactants are:Fe2+
(aq)
Cu2+(aq)
Fe(s)
Cu(s)
CHE118 3
Modifications to Experiment
Use the porous cup instead of the inverted U-tube.
CHE118 4
Porous Cup250 mL Beaker
Voltmeter
Three (or two) number scales are shown, use the 0 to 3 Volt scale (or 0 to 5 Volt scale)
Use the red 3 or 5 lead, not the red 15.
CHE118 5
Voltmeter
Anode to the (-) lead and the cathode to the (+) lead.
The alligator clips can clip onto the lead posts if the plastic coverings are as far up as they can go.
CHE118 6
Final Setup
CHE118 7
Handling of Porous Cup
• Please do not expose the cup to drastic temperature changes. Have the cup change temperature gradually.
• For cold temperatures, not too cold (5°C)
• Separate the porous cup and beaker; put each into an ice bath
CHE118 8
Calculations
ΔG = - nFE to calculate ΔG
ΔG = - RT lnKeq to calculate Keq
ΔS Graph ΔG vs. Temp (Kelvin), find slope
ΔH Rearrange ΔG = ΔH - T ΔS to solve for ΔH
CHE118 9
Clean-Up
• Please rinse the porous cup several times with tap water, then twice with deionized water.
• Clean the 250 mL beaker with soap and rinse well with tap water, then deionized water.
• Soak the porous cup in deionized water that is in the 250 mL beaker. Soak for several minutes.
CHE118 10
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