instruction:
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.
question:
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. 
answer:
Science


question:
Cardinal Thomas Gibbons' defense of this organization would lead to Pope Leo XIII issuing an encylical, Rerum Novarum, supporting organizations of their kind. In contrast with its inclusive reputation, a chapter of this group was involved in the Seattle riots of 1886. Internal feuding following the failed Missouri Pacific railroad strike of 1886, and the emergence of a rival organization of skilled craftsmen, meant that by 1900, this organization was almost nonexistent. Name this labor organization that helped lobby for the Chinese Exclusion Act and, for 10 points, was founded by nine tailors in Philadelphia in 1869 and reached its peak under Terence V. Powderly.
answer:
History


question:
plots, which relate the boiling point of a solution to the boiling point of water, can only be applied in conditions where this relation holds. Its namesake also names the cryoscopic and ebullioscopic constants used in Van't Hoff's rule. Positive and negative deviations from it are characteristic of azeotropes, and another formulation of this statement, which applies to components whose concentration limits to zero, is called Henry's law. For 10 points, identify this eponymous law which states that for an ideal solution, the vapor pressure can be described as a sum of the products of the pressure for each component times the mole fraction.
answer:

Science