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1. The physical or chemical process by which a substance in one state becomes incorporated into and retained by another substance of a different state. Absorption differs from adsorption in that the first substance permeates the entire bulk of the second substance, rather than just adhering to the surface. 2.
Hard water. A bathtub faucet with built-up calcification from hard water in Southern Arizona. Hard water is water that has a high mineral content (in contrast with "soft water"). Hard water is formed when water percolates through deposits of limestone, chalk or gypsum, [ 1] which are largely made up of calcium and magnesium carbonates ...
Hard tissue. Hard tissue, refers to "normal" calcified tissue, is the tissue which is mineralized and has a firm intercellular matrix. [ 1] The hard tissues of humans are bone, tooth enamel, dentin, and cementum. [ 2] The term is in contrast to soft tissue .
Osmium (from Ancient Greek ὀσμή (osmḗ) 'smell') is a chemical element; it has symbol Os and atomic number 76. It is a hard, brittle, bluish-white transition metal in the platinum group that is found as a trace element in alloys, mostly in platinum ores. Osmium is the densest naturally occurring element. When experimentally measured using ...
A desiccant is a hygroscopic substance that is used to induce or sustain a state of dryness (desiccation) in its vicinity; it is the opposite of a humectant. Commonly encountered pre-packaged desiccants are solids that absorb water. Desiccants for specialized purposes may be in forms other than solid, and may work through other principles, such ...
Base (chemistry) Soaps are weak bases formed by the reaction of fatty acids with sodium hydroxide or potassium hydroxide. In chemistry, there are three definitions in common use of the word " base ": Arrhenius bases, Brønsted bases, and Lewis bases. All definitions agree that bases are substances that react with acids, as originally proposed ...
Cement is seldom used on its own, but rather to bind sand and gravel ( aggregate) together. Cement mixed with fine aggregate produces mortar for masonry, or with sand and gravel, produces concrete. Concrete is the most widely used material in existence and is behind only water as the planet's most-consumed resource.
Salt (chemistry) The crystal structure of sodium chloride, NaCl, a typical salt. The purple spheres represent sodium cations, Na +, and the green spheres represent chloride anions, Cl −. The yellow stipples show the electrostatic forces. In chemistry, a salt or ionic compound is a chemical compound consisting of an assembly of positively ...