Carbon-12 Carbon-12 Carbon-12 (C) is the more abundant of the two stable isotopes of carbon (Carbon-13 being the other), amounting to 98.93% of the element carbon; its abundance is due to the triple-alpha process by which it is created in stars. Carbon-12 is of particular importance in its use as the standard from which atomic masses of all nuclides are measured, thus, its atomic mass is exactly 12 daltons by definition. Its nucleus contains 6 protons and 6 neutrons. Before 1959 both the IUPAP and IUPAC used oxygen to define the mole; the chemists defining the mole as the number of
Standard weight in fish common measures of condition used in fisheries assessment and management. Fulton’s condition factor, K, is another measure of an individual fish’s health that uses standard weight. Proposed by Fulton in 1904, it assumes that the standard weight of a fish is proportional to the cube of its length: formula_2 where "W" is the whole body wet weight in grams and "L" is the length in centimeters; the factor 100 is used to bring K close to a value of one. Standard weight in fish Standard weight in fish is the typical or expected weight at a given total length for