In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.

[EX Q]: First proposed by Lewis, it is related logarithmically to a gas's standard Gibbs free energy divided by the temperature and gas constant. At equilibrium, this quantity must be equal in both gas and liquid phases. Taking the derivative of the natural log of this function is equates it to the derivative of a reaction's chemical potential. Equal to the gas' pressure when the gas is ideal, FTP, identify this thermodynamic quantity which replaces partial pressure when working with real gases and describes the tendency of a substance to escape from its current phase, symbolized by f.
[EX A]: Science

[EX Q]: An approximation of it named for Russell uses the TDS value to determine one of its parameters via the Langelier approximation, while one constant that appears in it has units of moles per kilogram to the one half power, according the Bates-Guggenheim convention. Along with Guggenheim, Scatchard and Bronsted improved upon this model by developing the SIT theory, and that model has a better fit than a modification of it named for Davies. This relationship assumes the existence of only long-range interactions, and it was extended to account for Brownian motion by Lars Onsager. It assumes that the solvent is structure-less and that the solution is dilute, and the theory behind it implies that the electrostatic potential falls off exponentially when r is greater than the atomic radius due to screening by counter ions. For 10 points, identify this equation which is used to calculate the activity coefficients, and is named for a German and a Dutch scientist. 
[EX A]: Science

[EX Q]: One character in this work sings the aria Parmi veder la lagrime after learning about the abduction of a character whom he met earlier when disguised as Gualtier Mald. That character is the subject of the aria Caro Nome and at the beginning of this work he sings Quaesta o Quella when he attempts to seduce Countess Ceprano. Based on Victor Hugos play Le Roi samuse, the title character is cursed by Monterone for aiding the Duke of Mantua in his flings and unwittingly aids in the abduction of his daughter Gilda, who is killed by the assassin Sparafucile. Featuring the aria La donna  mobile, for 10 points, identify this Giuseppe Verdi opera about a hunchbacked court jester.
[EX A]:
Fine Arts