Final answer:
The standard cell potential is determined by calculating the difference between the electrode potentials of the cathode and anode under standard conditions. Standard conditions are usually at a concentration of 1 M, a pressure of 1 atm and a temperature of 298 K. The standard hydrogen electrode (SHE) is used as a reference point with a standard potential of 0 V.
Step-by-step explanation:
To find the cell potential, we need to calculate the difference in standard electrode potentials. This is because the potential of a single electrode cannot be measured in isolation; only the potential difference between two electrodes can be established. The standard cell potential, denoted as E°cell, is defined as the potential of a cell measured under standard conditions. These standard conditions typically include solutions at 1 M concentration, gases at 1 atm pressure, and a temperature of 298 K (25°C).
The cell potential is computed as Ecell = Ecathode − Eanode. The half-cell with a reduction taking place is considered the cathode, and its potential is expressed as Ecathode. Meanwhile, the half-cell undergoing oxidation is the anode, with its potential referenced as Eanode. To facilitate a standard scale for comparison of electrode potentials, the scientific community uses the standard hydrogen electrode (SHE) as a universal reference with a potential of exactly 0 V.
An example of calculating a standard cell potential is provided when we consider a Zn/Cu galvanic cell, where the potential difference between the two half-reactions is measured and the standard cell potential can then be derived. Tabulated values of standard electrode potentials allow for accurate and convenient calculations when predicting the feasibility and spontaneity of redox reactions.