Names | |
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IUPAC name Potassium carbonate | |
Other names Carbonate of potash, dipotassium carbonate, sub-carbonate of potash, pearl ash, potash, salt of tartar, salt of wormwood. | |
Identifiers | |
3D model (JSmol) | |
ChEBI | |
ChemSpider | |
ECHA InfoCard | 100.008.665 |
E number | E501(i) (acidity regulators, ...) |
PubChem CID | |
RTECS number |
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UNII |
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CompTox Dashboard (EPA) | |
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Properties | |
K 2CO 3 | |
Molar mass | 138.205 g/mol |
Appearance | White, hygroscopic solid |
Density | 2.43 g/cm3 |
Melting point | 891 °C (1,636 °F; 1,164 K) |
Boiling point | Decomposes |
110.3 g/100 mL (20 °C) 149.2 g/100 mL (100 °C) | |
Solubility | |
Acidity (pKa) | 10.25 |
−59.0·10−6 cm3/mol | |
Thermochemistry [1] | |
Heat capacity (C) | 114.4 J·mol−1·K−1 |
Std molar entropy (S⦵298) | 155.5 J·mol−1·K−1 |
Std enthalpy of formation (ΔfH⦵298) | −1151.0 kJ·mol−1 |
Gibbs free energy (ΔfG⦵) | −1063.5 kJ·mol−1 |
Enthalpy of fusion (ΔfH⦵fus) | 27.6 kJ·mol−1 |
Hazards | |
GHS labelling: | |
Warning | |
H302, H315, H319, H335 | |
P261, P305+P351+P338 | |
NFPA 704 (fire diamond) | |
Flash point | Non-flammable |
Lethal dose or concentration (LD, LC): | |
LD50 (median dose) | 1870 mg/kg (oral, rat) [2] |
Safety data sheet (SDS) | ICSC 1588 |
Related compounds | |
Other anions | Potassium bicarbonate |
Other cations | Lithium carbonate Sodium carbonate Rubidium carbonate Caesium carbonate |
Related compounds | Ammonium carbonate |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Potassium carbonate is the inorganic compound with the formula K2 CO3. It is a white salt, which is soluble in water and forms a strongly alkaline solution. It is deliquescent, often appearing as a damp or wet solid. Potassium carbonate is mainly used in the production of soap and glass. [3] Commonly, it can be found as the result of leakage of alkaline batteries. [4]
Potassium carbonate is the primary component of potash and the more refined pearl ash or salts of tartar. The first patent issued by the US Patent Office was awarded to Samuel Hopkins in 1790 for an improved method of making potash and pearl ash. [5] [6]
In late 18th-century North America, before the development of baking powder, pearl ash was used as a leavening agent for quick breads. [7] [8]
Potassium lye (which in this case can alternatively be called potash), a substance which contains potassium carbonate, potassium bicarbonate, and potassium hydroxide, [9] [10] was historically produced by dissolving the lye found in the wooden ashes inside of water for at least 24 hours, disposing of the undissolved ashes, and then drying/evaporating the remaining liquid. [9] [11]
With modern observation, this process would produce greater yields if done with the ashes of banana peels due to their increased amounts of potassium carbonate. [11]
As previously mentioned, Samuel Hopkins created an improved method of making pearl ash. One of those procedures was putting the lye/potash in a kiln to remove impurities.
Today, potassium carbonate is prepared commercially by the reaction of potassium hydroxide with carbon dioxide: [3]
From the solution crystallizes the sequestrate K2CO3·3⁄2H2O ("potash hydrate"). Heating this solid above 200 °C (392 °F) gives the anhydrous salt. In an alternative method, potassium chloride is treated with carbon dioxide in the presence of an organic amine to give potassium bicarbonate, which is then calcined:
In chemistry, an alkali is a basic, ionic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The adjective alkaline, and less often, alkalescent, is commonly used in English as a synonym for basic, especially for bases soluble in water. This broad use of the term is likely to have come about because alkalis were the first bases known to obey the Arrhenius definition of a base, and they are still among the most common bases.
A carbonate is a salt of carbonic acid, H2CO3, characterized by the presence of the carbonate ion, a polyatomic ion with the formula CO2−3. The word "carbonate" may also refer to a carbonate ester, an organic compound containing the carbonate groupO=C(−O−)2.
Potash includes various mined and manufactured salts that contain potassium in water-soluble form. The name derives from pot ash, plant ashes or wood ash soaked in water in a pot, the primary means of manufacturing potash before the Industrial Era. The word potassium is derived from potash.
Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations Na+ and hydroxide anions OH−.
Sodium bicarbonate (IUPAC name: sodium hydrogencarbonate), commonly known as baking soda or bicarbonate of soda, is a chemical compound with the formula NaHCO3. It is a salt composed of a sodium cation (Na+) and a bicarbonate anion (HCO3−). Sodium bicarbonate is a white solid that is crystalline, but often appears as a fine powder. It has a slightly salty, alkaline taste resembling that of washing soda (sodium carbonate). The natural mineral form is nahcolite. It is a component of the mineral natron and is found dissolved in many mineral springs.
Sodium carbonate is the inorganic compound with the formula Na2CO3 and its various hydrates. All forms are white, odourless, water-soluble salts that yield alkaline solutions in water. Historically, it was extracted from the ashes of plants grown in sodium-rich soils, and because the ashes of these sodium-rich plants were noticeably different from ashes of wood, sodium carbonate became known as "soda ash". It is produced in large quantities from sodium chloride and limestone by the Solvay process, as well as by carbonating sodium hydroxide which is made using the Chlor-alkali process.
Baking powder is a dry chemical leavening agent, a mixture of a carbonate or bicarbonate and a weak acid. The base and acid are prevented from reacting prematurely by the inclusion of a buffer such as cornstarch. Baking powder is used to increase the volume and lighten the texture of baked goods. It works by releasing carbon dioxide gas into a batter or dough through an acid–base reaction, causing bubbles in the wet mixture to expand and thus leavening the mixture. The first single-acting baking powder was developed by food manufacturer Alfred Bird in England in 1843. The first double-acting baking powder, which releases some carbon dioxide when dampened and later releases more of the gas when heated by baking, was developed by Eben Norton Horsford in the U.S. in the 1860s.
In cooking, a leavening agent or raising agent, also called a leaven or leavener, is any one of a number of substances used in doughs and batters that cause a foaming action that lightens and softens the mixture. An alternative or supplement to leavening agents is mechanical action by which air is incorporated. Leavening agents can be biological or synthetic chemical compounds. The gas produced is often carbon dioxide, or occasionally hydrogen.
Potassium hydroxide is an inorganic compound with the formula KOH, and is commonly called caustic potash.
Potassium bicarbonate (IUPAC name: potassium hydrogencarbonate, also known as potassium acid carbonate) is the inorganic compound with the chemical formula KHCO3. It is a white solid.
Ammonium bicarbonate is an inorganic compound with formula (NH4)HCO3. The compound has many names, reflecting its long history. Chemically speaking, it is the bicarbonate salt of the ammonium ion. It is a colourless solid that degrades readily to carbon dioxide, water and ammonia.
Dutch processed cocoa, Dutch cocoa, or alkalized cocoa, is cocoa solids that have been treated with an alkalizing agent to reduce the natural acidity of cocoa, giving it a less bitter taste compared to "natural cocoa" extracted with the Broma process. It forms the basis for much of modern chocolate, and is used in ice cream, hot chocolate, and baking.
The Leblanc process was an early industrial process for making soda ash used throughout the 19th century, named after its inventor, Nicolas Leblanc. It involved two stages: making sodium sulfate from sodium chloride, followed by reacting the sodium sulfate with coal and calcium carbonate to make sodium carbonate. The process gradually became obsolete after the development of the Solvay process.
An ashery is a factory that converts hardwood ashes into lye, potash, or pearlash. Asheries were common in newly settled areas of North America during the late 18th century and much of the 19th century, when excess wood was available as settlers cleared their land for farming. Hardwood ashes contain abundant levels of potassium carbonate and potassium hydroxide, the principal components of the products being produced.
In analytical chemistry, ashing or ash content determination is the process of mineralization for preconcentration of trace substances prior to a chemical analysis, such as chromatography, or optical analysis, such as spectroscopy.
Dry cocoa solids are the components of cocoa beans remaining after cocoa butter, the fatty component of the bean, is extracted from chocolate liquor, roasted cocoa beans that have been ground into a liquid state. Cocoa butter is 46% to 57% of the weight of cocoa beans and gives chocolate its characteristic melting properties. Cocoa powder is the powdered form of the dry solids with a small remaining amount of cocoa butter. Untreated cocoa powder is bitter and acidic. Dutch process cocoa has been treated with an alkali to neutralize the acid.
Cleaning agents or hard-surface cleaners are substances used to remove dirt, including dust, stains, foul odors, and clutter on surfaces. Purposes of cleaning agents include health, beauty, removing offensive odor, and avoiding the spread of dirt and contaminants to oneself and others. Some cleaning agents can kill bacteria and clean at the same time. Others, called degreasers, contain organic solvents to help dissolve oils and fats.
Wood ash is the powdery residue remaining after the combustion of wood, such as burning wood in a fireplace, bonfire, or an industrial power plant. It is largely composed of calcium compounds along with other non-combustible trace elements present in the wood. It has been used for many purposes throughout history.
Condensed aerosol fire suppression is a particle-based method of fire extinction. It is similar to but not identical to dry chemical fire extinction methods, using an innovative pyrogenic, condensed aerosol fire suppressant. It is a highly effective fire suppression method for class A, B, C, E and F. Some aerosol-generating compounds produce a corrosive by-product that may damage electronic equipment, although later generations lower the effect.
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