One equation for describing these phenomena equates the derivative of pressure with respect to temperature to the inverse of temperature times the change in volume; that equation is named for Clausius and Clapeyron ("KLAH-peh-rohn").
In polymer solutions, these phenomena occurs through a process called spinodal decomposition, and one of these that does not break symmetry occurs in the two-dimensional XY model and is of infinite order. Continuous ones can be sorted into universality classes by their critical exponents. One equation for describing these phenomena equates the derivative of pressure with respect to temperature to the inverse of temperature times the change in volume; that equation is named for Clausius and Clapeyron ("KLAH-peh-rohn"). Black postulated a form of energy that is absorbed or released during this phenomenon without causing a change in temperature, known as latent heat. For 10 points, name this type of physical phenomenon whose variants include deposition, sublimation, and melting.
In polymer solutions, these phenomena occurs through a process called spinodal decomposition, and one of these that does not break symmetry occurs in the two-dimensional XY model and is of infinite order.
phase transition [accept equivalents like phase change; accept separation before "XY model"]