Calcium bicarbonate

Calcium bicarbonate
IUPAC nameCalcium bicarbonate
Other namesCalcium hydrogencarbonate
Properties
Molecular formulaCa(HCO3)2
Molar mass162.11464 g/mol
Solubility in water16.6 g/100 ml (20°C)
Hazards
Flash point?°C
Except where noted otherwise, data are given for
materials in their standard state
(at 25 C, 100 kPa)



Calcium bicarbonate (Ca(HCO3)2), also called calcium hydrogen carbonate, does not refer to a known solid compound; it “exists” only in a solution containing the ions calcium Ca2+, dissolved carbon dioxide CO2, bicarbonate HCO3, and carbonate CO32–. The relative concentrations of these carbon-containing species depend on the pH; bicarbonate predominates within the range 6-10.

All waters in contact with the atmosphere absorb carbon dioxide, and as these waters come into contact with rocks and sediments they acquire metal ions, most commonly calcium and magnesium, so most natural waters that come from streams, lakes, and especially wells, can be regarded as dilute solutions of these bicarbonates. These hard waters tend to form carbonate scale in pipes and boilers and they react with soaps to form an undesirable scum.

Attempts to prepare compounds such as calcium bicarbonate by evaporating its solution to dryness invariably yield the solid carbonate instead: Ca(HCO3)2(aq) → CO2(g) + H2O(l) + CaCO3(s). Very few solid bicarbonates other than those of the alkali metals are known to exist.

The above reaction is very important to the formation of stalactites, stalagmites, columns, and other speleothems within caves and, for that matter, in the formation of the caves themselves. As water containing carbon dioxide (including extra CO2 acquired from soil organisms) passes through limestone or other calcium carbonate containing minerals, it dissolves part of the calcium carbonate and hence becomes richer in bicarbonate. As the groundwater enters the cave, the excess carbon dioxide is released from the solution of the bicarbonate, causing the much less soluble calcium carbonate to be deposited.

Reference

IUPAC nomenclature is a system of naming chemical compounds and of describing the science of chemistry in general. It is developed and kept up to date under the auspices of the International Union of Pure and Applied Chemistry (IUPAC).
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A chemical formula is a concise way of expressing information about the atoms that constitute a particular chemical compound. A chemical formula is also a short way of showing how a chemical reaction occurs.
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Molar mass, symbol M,[1] is the mass of one mole of a substance (chemical element or chemical compound).[2] It is a physical property which is characteristic of each pure substance.
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Solubility is a physical property referring to the ability for a given substance, the solute, to dissolve in a solvent.[1] It is measured in terms of the maximum amount of solute dissolved in a solvent at equilibrium. The resulting solution is called a saturated solution.
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Water is a common chemical substance that is essential to all known forms of life.[1] In typical usage, water refers only to its liquid form or state, but the substance also has a solid state, ice, and a gaseous state, water vapor.
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The flash point of a flammable liquid is the lowest temperature at which it can form an ignitable mixture in air. At this temperature the vapor may cease to burn when the source of ignition is removed.
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standard state of a material is its state at 1 bar (100 kilopascals exactly). This pressure was changed from 1 atm (101.325 kilopascals) by IUPAC in 1990.[1] The standard state of a material can be defined at any given temperature, most commonly 25 degrees Celsius,
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This article has been tagged since October 2007.
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Calcium carbonate is a chemical compound, with the chemical formula CaCO3. It is a common substance found as rock in all parts of the world, and is the main component of shells of marine organisms, snails, and eggshells.
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The alkali metals are a series of elements comprising Group 1 (IUPAC style) of the periodic table: lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr).
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stalactite (Greek stalaktites, (Σταλακτίτης), from the word for "drip" and meaning "that which drips") is a type of speleothem (secondary mineral) that hangs from the ceiling or wall of limestone caves.
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stalagmite (from the Greek stalagma ("Σταλαγμίτης"), "drop" or "drip") is a type of speleothem that rises from the floor of a limestone cave due to the dripping of mineralized solutions and the deposition of calcium
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speleothem (from the Greek for "cave deposit") is a secondary mineral deposit formed in caves. It is the formal term for what is also known as a cave formation.

In limestone and dolostone caves

Overview


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cave is a natural underground void large enough for a human to enter. Some people suggest that the term 'cave' should only apply to cavities that have some part which does not receive daylight; however, in popular usage, the term includes smaller spaces like sea caves, rock
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