Question

(a) Which electrode of a voltaic cell, the cathode or the anode, corresponds to the higher potential energy for the electrons? (b) What are the units for electrical potential? How does this unit relate to energy expressed in joules?

Short answer

(a) In a voltaic cell, the anode has higher potential energy for electrons as oxidation occurs at the anode and electrons flow towards the cathode. (b) The unit for electrical potential is the volt (V). The relationship between electrical potential and energy (in joules) can be expressed as: \(1\,V = 1\,J/C\), where V represents volts, J represents joules, and C represents charge in coulombs.

Step-by-step solution

Identify the electrode with higher potential energy for electrons

In a voltaic cell, oxidation occurs at the anode, resulting in the generation of positive ions and the release of electrons. These electrons move through the external circuit towards the cathode, where reduction occurs. Due to the flow of electrons from the anode to cathode, the anode is considered to have more potential energy for the electrons.

Determine the unit for electrical potential

The unit for electrical potential is the volt (V), named after Alessandro Volta.

Relate electrical potential unit to energy expressed in joules

The potential energy of the electrons is converted into electrical potential energy when they move through the voltaic cell. Electrical potential can be expressed in energy terms since it is the work done per unit charge. The relationship between electrical potential (measured in volts) and energy (measured in joules) can be expressed as: \(1\,V = 1\,J/C\) Where V represents electrical potential in volts, J represents energy in joules, and C represents charge in coulombs. In other words, an electrical potential of 1 volt is equal to 1 joule of energy per coulomb of charge.