A question is given on the form n(mu(beta)-mu(alpha)) for the volume term of work of formation of critical Here, n is the number of molecule undergone the phase transition, mu denotes the chemical potential, alpha and beta represent the parent and nucleating phases, respectively. In this paper we concentrate transition without volume change. We have calculated the volume term in terms of the potential difference mu(re)-mu(eq) for this case. Here, mu(re) is the chemical potential of the reservoir and mu(eq) that the phase transition. We have W-vol = kappa(beta)-kappa(alpha)/2V(eq)(2) (mu(re) - mu(eq))V-2(beta) with kappa denoting the isothermal compressibility, nu(eq) being the molecular volume at the phase transition, V-beta the volume of the nucleus. (C) 2013 Elsevier B.V. All rights reserved.