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Potassium is the eighth or ninth most common element by mass (0.2%) in the human body, so that a 60 kg adult contains a total of about 120 g of potassium. [84] The body has about as much potassium as sulfur and chlorine, and only calcium and phosphorus are more abundant (with the exception of the ubiquitous CHON elements). [85]
Parts-per-million cube of relative abundance by mass of elements in an average adult human body down to 1 ppm. About 99% of the mass of the human body is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Only about 0.85% is composed of another five elements: potassium, sulfur, sodium, chlorine, and magnesium ...
For other isotopes, the isotopic mass is usually within 0.1 u of the mass number. For example, 35 Cl (17 protons and 18 neutrons) has a mass number of 35 and an isotopic mass of 34.96885. [7] The difference of the actual isotopic mass minus the mass number of an atom is known as the mass excess, [8] which for 35 Cl is –0.03115.
All other potassium isotopes have half-lives under a day, most under a minute. The least stable is 31 K, a three-proton emitter discovered in 2019; its half-life was measured to be shorter than 10 picoseconds. [5] [6] Stable potassium isotopes have been used for several nutrient cycling studies since potassium is a macronutrient required for ...
Potassium hydroxide is an inorganic compound ... Lower molecular-weight alcohols such as ... KOH and NaOH can be used interchangeably for a number of applications ...
More precisely, the first number ("N value") is the percentage of elemental nitrogen by weight in the fertilizer; that is, the mass fraction of nitrogen times 100. The second number ("P value") is the percentage by weight of phosphorus pentoxide P 2 O 5. The third number ("K value") is the equivalent content of potassium oxide K 2 O. [3]
Molecular weight (M.W.) (for molecular compounds) and formula weight (F.W.) (for non-molecular compounds), are older terms for what is now more correctly called the relative molar mass (M r). [8] This is a dimensionless quantity (i.e., a pure number, without units) equal to the molar mass divided by the molar mass constant .
Potassium-40 (40 K) is a long lived and the main naturally occurring radioactive isotope of potassium. Its half-life is 1.25 billion years. It makes up about 0.012% (120 ppm ) of natural potassium.