Calcium carbonate equilibrium pressure must exceed total atmospheric pressure of 101 kPa, which happens at 898 °C. Calcium carbonate is poorly soluble in pure water (47 mg/L at normal atmospheric CO partial pressure as shown below). The equilibrium of its solution is given by the equation (with dissolved calcium carbonate on the right): where the solubility product for [Ca] [CO] is given as anywhere from "K" = 3.7×10 to "K" = 8.7×10 at 25 °C, depending upon the data source. What the equation means is that the product of molar concentration of calcium ions (moles of dissolved Ca per liter of solution)
What If?: Serious Scientific Answers to Absurd Hypothetical Questions What If?: Serious Scientific Answers to Absurd Hypothetical Questions What If?: Serious Scientific Answers to Absurd Hypothetical Questions is a non-fiction book by Randall Munroe in which the author answers hypothetical science questions sent to him by readers of his webcomic, "xkcd". The book contains a selection of questions and answers originally published on his blog "What If?", along with several new ones. The book is divided into several dozen chapters, most of which are devoted to answering a unique question. "What If?" was released in September 2, 2014 and was received positively by critics. In the introduction section of