For 10 points, name this modification of the Ideal Gas Law, an equation of state named for a Dutch chemist.
Materials that obey this relation have an interparticle potential proportional to d over r to the 6th power, assuming r is greater than d. The isotherm of this equation below the critical temperature was modified by Maxwell to include a flat portion, which removes the metastable states. It assumes the material in question consists of hard spheres of equal radius, and can be derived as a first-order truncation of the virial equation. It contains parameters for inter-particle attraction and particle volume, or a and b respectively. For 10 points, name this modification of the Ideal Gas Law, an equation of state named for a Dutch chemist.
Materials that obey this relation have an interparticle potential proportional to d over r to the 6th power, assuming r is greater than d.
{Van Der Waals} equation of state