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Potassium sulfate (K 2 SO 4) has been known since early in the 14th century.It was studied by Glauber, Boyle, and Tachenius.In the 17th century, it was named arcanuni or sal duplicatum, as it was a combination of an acid salt with an alkaline salt.
K 2 SO 4 + 4 C → K 2 S + 4 CO. In the laboratory, pure K 2 S may be prepared by the reaction of potassium and sulfur in anhydrous ammonia. [4] Sulfide is highly basic, consequently K 2 S completely and irreversibly hydrolyzes in water according to the following equation: K 2 S + H 2 O → KOH + KSH. For many purposes, this reaction is ...
ca(oh) 2 + k 2 co 3 → caco 3 + 2 koh Filtering off the precipitated calcium carbonate and boiling down the solution gives potassium hydroxide ("calcinated or caustic potash"). This method of producing potassium hydroxide remained dominant until the late 19th century, when it was largely replaced by the current method of electrolysis of ...
For many substances, the formation reaction may be considered as the sum of a number of simpler reactions, either real or fictitious. The enthalpy of reaction can then be analyzed by applying Hess' law, which states that the sum of the enthalpy changes for a number of individual reaction steps equals the enthalpy change of the overall reaction.
The conversion between hydroxyl value and other hydroxyl content measurements is obtained by multiplying the hydroxyl value by the factor 17/560. [2] The chemical substance may be a fat, oil, natural or synthetic ester, or other polyol. [3] ASTM D 1957 [4] and ASTM E222-10 [5] describe several versions of this method of determining hydroxyl value.
In chemistry, acid value (AV, acid number, neutralization number or acidity) is a number used to quantify the acidity of a given chemical substance.It is the quantity of base (usually potassium hydroxide (KOH)), expressed as milligrams of KOH required to neutralize the acidic constituents in 1 gram of a sample.
For example, in the reaction CH 4 + 2 O 2 → CO 2 + 2 H 2 O, the stoichiometric number of CH 4 is −1, the stoichiometric number of O 2 is −2, for CO 2 it would be +1 and for H 2 O it is +2. In more technically precise terms, the stoichiometric number in a chemical reaction system of the i -th component is defined as
The standard Gibbs free energy of formation (G f °) of a compound is the change of Gibbs free energy that accompanies the formation of 1 mole of a substance in its standard state from its constituent elements in their standard states (the most stable form of the element at 1 bar of pressure and the specified temperature, usually 298.15 K or 25 °C).