Question

How is surface tension different from surface energy?

Answer 1

For a liquid, the surface tension (force per unit length) and the surface energy density are identical. Water has a surface energy density of 0.072 J/m^2 and a surface tension of 0.072 N/m; the units are equivalent. When a solution is formed comprising a mixture of two liquids or dissolved molecules, the surface tension of the primary liquid can deviate from corresponding pure liquid values. This phenomenon can be described by the Gibbs isotherm.