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Chemistry 19: 5-8

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Electrochemistry and Electrolysis

Chapter 19: 5-8 Homework

Reading Preparation

Textbook assignment: Read Kotz and Triechel, Chemistry and Chemical Reactivity Chapter 18: Sections 5 to 8.

Study Notes

Key Formula

Work wmax = nFE E: cell potential
nF: amount of electric charge transfered
Nernst Equation E   =   E °    ( RT nF )   ln   Q E: actual potential at temperature T
E°: potential at STP
n: number of moles of electrons transfered
F: total charge per mole electrons
R: gas constant
T: Temperature (K)
Q: reaction quotient
Nernst at STP (298.15K) E   =   E °    ( RT F ) 1 n   ln   Q   E = E °    0.0257 n   ln   Q    Constants R, T, F calculated
Free Energy (STP) ΔrG° = -nFE° G°: Gibbs free energy for reduction half-reaction
E°: electric potential change for reduction half-reaction
Free Energy and Nernst at Equilibrium E °  =   0.0257 n   ln   K    ln   K   =   nE ° 0.0257 E = 0 at equilibrium
Electron count i   = C t   i: current (Amps)
C: charge
t: time

Read the following weblecture before chat: Electrochemistry and Thermodynamics

Study Activity

Videos for Chapter 19: Principles of Chemical Reactivity: Entropy and Free Energy

Review the Videos at Thinkwell Video Lessons.

    • Galvanic Cells
      • The Nernst Equation
      • Electrochemical Determinants of Equilibria
    • Batteries
      • Batteries
    • Electrolysis and Electrolytic Cells
      • Electrolytic Cells
      • The Stoichiometry of Electrolysis

Use the Electrolysis Experiment simulation to run a virtual electrolysis experiment.

  • Read the Overview and Learning Outcomes, then click on "Experiment".
  • Select the option to run the Experiment.
  • Choose your own metals for the positive and negative terminals. Record thee masses of the electrodes.
  • Choose a solution from the dropdown menu.
  • Set the current to 1.00 amp.
  • Set the timer to 5:00 minutes (300 seconds).
  • Turn the ammeter on to run the experiment.
    • Which metal is the anode? Which is the cathode?
    • What is the initial mass of the anode? Of the cathode?
    • What are the final masses of each electrode?
    • Which increased in mass? Which decreased in mass?
    • Which way do the electrons flow?
  • Click the rerun button on the ammeter to repeat the experiment with these electrodes at least three more times
    • 2.00 amps and 5 minutes
    • 3.00 amps and 5 minutes
    • 2.00 amps and 10 minutes
    • For each run
      • Record the starting masses of the anodes for each run.
      • Record the final masses of the anodes for each run.
    • How does changing the time affect the mass change?
    • How does changing the current affect the mass change?
    • Repeat the experiment with different electrodes.

Chat Preparation Activities

Chapter Quiz

(Aligns to) AP LAB #16 GUIDED INQUIRY — — Building an Electrochemical cell — Phase III

Use your batteries (or commercial batteries) to observe the results of electrolysis on common molecules and rank results. Write and post your formal report.