Electrode Potentials and Electrochemical Cells: Electrode Potentials and Cells

Oxidation

Loss of electrons (Increase in oxidation state)

Reduction

Gain of electrons (Decrease in oxidation state)

Oxidising agent

Species that accepts electrons

Reducing agent

Species that donates electrons

What are the standard conditions:

• Pressure

• Temperature

• Concentration

• 100kPa

• 298K

• 1 mol dm^-3

Where does oxidation occur?

Negative electrode

Where does reduction occur?

Positive electrode

What does the standard electrode potential of a half cell indicate?

Its tendency to lose electrons/undergo oxidation (more negative electrode potential) or gain electrons/undergo reduction (more positive electrode potential)

Standard electrode potential

The electromotive force of a half-cell compared with a standard hydrogen half cell in standard conditions

Explain the function of the salt bridge

• The ions flow through the salt bridge

• To complete the circuit

What are the conditions for the standard hydrogen electrode? (4 points)

• 100kPa H_{2 (g)}

• 1 mol dm^-3 H⁺ _(aq)

• 298 K

• Solid platinum electrode

Explain 3 ways how the salt bridge provides electrical connection between the two solutions

• Has mobile ions

• Balances the charge

• Complete the circuit

What does NOPR stand for?

• Negative

• Oxidised

• Positive

• Reduced

Cell potential equation

Cell potential = Electrode potential (Right Hand Side) - Electrode potential (Left Hand Side)

How do you draw a conventional representation of a cell (4 points)?

• Double vertical line = Salt bridge in middle

• Vertical single line = Phase boundary

• Standard hydrogen electrode/ More negative electrode = Left side of salt bridge

• Species with highest oxidation state = Next to salt bridge