Redox 5

SHE = Standard Hydrogen Electrode

Reference Electrode (since the potential of an electrode can NOT be measured by itself) = hydrogen The hydrogen electrode = 0V

CONDITIONS FOR 0V: Temperature: 25˚C Pressure: 1 atm [H+]: 1 mol/dm3

Electrode Potential = Reduction Half Cells

Use Table 14 in IB Data Booklet

NEGATIVE Electrode Potential: Oxidation happens at the METAL Stronger reducing agent than H2 (g)

POSITIVE Electrode Potential: Reduction happens at the METAL Weaker reducing agent than H2 (g)

VS

METHOD 1: HALF STEP EQUATIONS

Steps: Write Half Cell Equations Flip (if necessary) to balance electrons [Therefore, E˚ x -1] Add the cell potential together

NOTE:Standard Electrodes ≠ Moles

Positive E˚ Cell Potential = Spontaneous Negative E˚ Cell Potential = Non- Spontaneous

METHOD 2: FORMULA

Oxidation: Half cell with MORE reactive metalReduction: Half cell with LESS reactive metal

Nature of Electrode Temperature Concentration of Electrolyte

Ov

Over time, the voltaic cell will be dead (e.g. a dead battery)

SHE

Predicting Cell Potentials

Factors affecting Cell Potentials

Dead Cell