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Download QR code; Print/export Download as PDF; Printable version; In other projects Wikidata item; ... Mohs hardness [1] Vickers hardness (MPa) [1] Brinell hardness
Degrees of general hardness (dGH or °GH) is a unit of water hardness, specifically of general hardness. General hardness is a measure of the concentration of divalent metal ions such as calcium (Ca 2+) and magnesium (Mg 2+) per volume of water. Specifically, 1 dGH is defined as 10 milligrams (mg) of calcium oxide (CaO) per litre of
Carbonate hardness is a measure of the concentration of carbonates such as calcium carbonate (CaCO 3) and magnesium carbonate (MgCO 3) per volume of water. As a unit 1 dKH is the same as 1 °dH which is equal to approximately 0.1786 mmol/L or 17.86 milligrams (mg) of calcium carbonate per litre of water, i.e. 17.86 ppm.
Carbonate hardness, is a measure of the water hardness caused by the presence of carbonate (CO 2− 3) and bicarbonate (HCO − 3) anions. Carbonate hardness is usually expressed either in degrees KH (from the German "Karbonathärte"), or in parts per million calcium carbonate ( ppm CaCO 3 or grams CaCO 3 per litre|mg/L).
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, bicarbonates and sulfates.
The grain per gallon (gpg) is a unit of water hardness defined as 1 grain (64.8 milligrams) of calcium carbonate dissolved in 1 US gallon of water (3.785412 L). It translates into 1 part in about 58,000 parts of water or 17.1 parts per million (ppm). Also called Clark degree (in terms of an imperial gallon).
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Water can remain in a liquid state at high temperatures in the deep ocean or underground. For example, temperatures exceed 205 °C (401 °F) in Old Faithful, a geyser in Yellowstone National Park. [66] In hydrothermal vents, the temperature can exceed 400 °C (752 °F). [67] At sea level, the boiling point of water is 100 °C (212 °F). As ...