This lecture series will cover:

1. Principles, oxidation numbers and states and electrochemical cells

2. Standard potential, direction and Gibb’s free energy

3. The Nernst equation

 

Key reactions:

• Oxidation is the loss of electrons and reduction is the gain of electrons

• Redox reactions are when oxidation and reduction occur simultaneously as when species loses electrons which are donated to and gained by the other species

• This can be divided into separate chemical equations:

  • Net ionic:     Cu2+ + Zn → Cu + Zn2+

  • Oxidation:   Zn → Zn2+ + 2 e-

  • Reduction:   Cu2+ + 2 e- → Cu

 

Oxidation number:

• The oxidation state of an element is 0

• Oxidation states in a neutral compound add up to zero and in an charge compound they add up to the total charge

• Some key ones to remember:

  • Hydrogen has an oxidation state of +1

  • Oxygen has an oxidation state of -2

  • All halogens have an oxidation state of -1

  • Group I metals have an oxidation state of +1

 

Electrochemical cells:

• Electrochemical cells used redox reactions as the electron transfer between products to create a flow of electrons

• The flow of electrons creates a electric current

• The potential difference between the two nodes can be measured to calculate the oxidation number of the anode (site of oxidation) and cathode (site of reduction)