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:
When it interacts with ryanodine receptors, this element upregulates its own release, and this compound forms the cell plates of coccolithophores. Stimulation of Gq ("g-sub-q") opens a channel that allows for this ion's movement, and proteins that bind this ion have an EF hand motif. Cellular concentrations of this ion are regulated by IP3. Parafollicular cells of the (*) thyroid produce a compound that reduces the concentration of this ion in blood, and its intestinal absorption requires vitamin D. This ion interacts with Troponin to stimulate muscle contraction, and the lumens of sarcoplasmic reticula have high concentrations of this ion. For 10 points, name this divalent cation that is stored in bones.
answer:
Science

question:
This philosopher claimed that mathematics instills "a habit of reasoning closely and in train" in a work which also argues that those who know a smattering of everything are far from attaining truth. This author of On the Conduct of the Understanding also argued that having a variety of religious groups helps prevent civil unrest but condemned Roman Catholics and atheists in A (*) Letter Concerning Toleration. This thinker postulated that the role of government was to protect its people's natural rights of life, liberty, and property and claimed that the mind was a "tabula rasa" in An Essay Concerning Human Understanding. For ten points, name this English Enlightenment philosopher who discussed the social contract in his Two Treatises of Government.
answer:
Social Science