[<< wikibooks] OCR Advanced GCE in Chemistry/Electrode potentials/Answers
1. An electrochemical cell is an exothermic reaction set up as two half-cells in two separate containers so that the energy released can produce current between them
A half-cell is half of an electrochemical cell. One half-cell supplies electrons, the other half-cell receives electrons
2. 0.76V
3. The salt bridge allows movement of ions between the two half-cells completing the circuit. This can simply be filter paper soaked in potassium nitrate solution 
4. see page
5. Change the conditions, they will no longer be standard values but E values. This can shift the equilibrium of a reaction and its E value
6. Reaction rate