Electrochemistry

Question 1

Describe the purpose of a salt bridge

Answer 1

A salt bridge is necessary to allow a current to flow around the circuit - to complete the circuit.
It also allows for charge neutralisation and prevents the development of a liquid junction potential.

Question 2

Why do we need two compartments in a concentration cell

Answer 2

If there was only one compartment, then instead of two concentrations it would be one average concentration - no voltage would be recorded

Question 3

explain what is meant by standard conditions in the context of an electrochemical cell

Answer 3

The well-defined set of reference under which the electrochemical properties of a cell are measured and compared.
* temperature = 298K
* pressure = 1 bar
* concentration = 1 M
* pure solids and liquids are in their standard states
* no current flow (equilibrium conditions)

Question 4

explain why the measured cell emf depends on the concentrations of species involved