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.

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. 

A: Science
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Q: This entity shares its name with one controlled by the astronomer and investigator of mesmerism, Jean Sylvain Bailly. It saw the execution of General Lecomte, and Marshall MacMahon led a campaign against it that culminated with a mass execution at the Wall of the Federalists. Its aftermath saw a mass deportation to New Caledonia, and it was opposed by Adolphe Thiers. Louis-Auguste Blanqui was its nominal leader despite being imprisoned at the time, and it ended in the "Bloody Week" amidst fierce barricade fighting. Growing out of the Franco-Prussian War, for 10 points, name this socialist government that held power for two months in 1871 in the French capital.

A: History
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Q: Removal of one of these objects from a carbonyl creates an enolate. Their magnetic resonance is used in the form of NMR that has typical chemical shifts of zero to twelve. One of them is transformed in electron capture. While they do not exist freely in solution, they can combine with water to form a (*) hydronium (""high""-DRO-nee-um) ion. The Bronsted-Lowry definition describes acids as donators of these particles. For 10 points, name this positive particle found in the nucleus.

A:
Social Science
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