Question

(a) What does the term electromotive force mean? (b) What is the definition of the volt? (c) What does the term cell potential mean?

Short answer

(a) Electromotive force (EMF) is the electrical energy per unit charge produced by an energy source, like a battery or a generator, that drives the flow of electrons in a circuit. It is measured in volts (V). (b) The volt (V) is the unit of electric potential difference in the International System of Units (SI) and is defined as the potential difference across a conductor when a current of one ampere dissipates one watt of power (1 V = 1 W/A). (c) Cell potential, also known as electrode potential or EMF in electrochemical cells, is the difference in electric potential between two electrodes, which drives the flow of electrons during a redox reaction. It is expressed in volts (V) and is responsible for the conversion of chemical energy into electrical energy or vice versa in an electrochemical cell.

Step-by-step solution

(a) Understanding Electromotive Force)

Electromotive force (EMF) is the electrical energy per unit charge that is produced by an energy source, like a battery or a generator. It can be seen as the force that pushes the electrons through a conductor, giving rise to an electric current. In other words, it is the energy source that drives the flow of electrons in a circuit. EMF is measured in volts (V).

(b) Definition of the Volt)

The volt (V) is the unit of electric potential difference in the International System of Units (SI). It is defined as the potential difference across a conductor when a current of one ampere dissipates one watt of power. Mathematically, 1 V = 1 W/A, where W is the power in watts (energy per unit time) and A is the current in amperes (charge per unit time). In the context of electrochemistry, a volt can also be presented as the energy required to move 1 mole of electrons (also called charge) through a potential difference of 1 volt (1 V = 1 J/C, where J is the energy in joules and C is the charge in coulombs).

(c) Understanding Cell Potential)

Cell potential, also known as electrode potential or electromotive force (EMF) in the context of electrochemical cells, is the difference in electric potential between the two electrodes of a cell, which drives the flow of electrons during a redox reaction. This electric potential difference is created due to the tendency of chemical species to lose or gain electrons (i.e., their redox potential). The cell potential is usually measured as the potential difference between two electrodes when no current is flowing (i.e., under equilibrium conditions) and is expressed in volts (V). This potential difference in an electrochemical cell is mainly responsible for the conversion of chemical energy into electrical energy or vice versa, depending on whether the cell is working as a battery or an electrolytic cell.