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Ammonium iron(II) sulfate, or Mohr's salt, is the inorganic compound with the formula (NH 4) 2 SO 4 ·Fe(SO 4)·6H 2 O. Containing two different cations, Fe 2+ and NH + 4, it is classified as a double salt of ferrous sulfate and ammonium sulfate. It is a common laboratory reagent because it is readily crystallized, and crystals resist oxidation ...
A mixture of ammonia gas and water vapor is introduced into a reactor that contains a saturated solution of ammonium sulfate and about 2% to 4% of free sulfuric acid at 60 °C. Concentrated sulfuric acid is added to keep the solution acidic, and to retain its level of free acid. The heat of reaction keeps reactor temperature at 60 °C.
Ammonium sulfate is an inorganic salt with a high solubility that disassociates into ammonium (NH + 4) and sulfate (SO 2− 4) in aqueous solutions. [1] Ammonium sulfate is especially useful as a precipitant because it is highly soluble, stabilizes protein structure, has a relatively low density, is readily available, and is relatively inexpensive.
The following chart shows the solubility of various ionic compounds in water at 1 atm pressure and room temperature (approx. 25 °C, 298.15 K). "Soluble" means the ionic compound doesn't precipitate, while "slightly soluble" and "insoluble" mean that a solid will precipitate; "slightly soluble" compounds like calcium sulfate may require heat to precipitate.
An example of a reaction forming an ammonium ion is that between dimethylamine, (CH 3) 2 NH, and an acid to give the dimethylammonium cation, [(CH 3) 2 NH 2] +: Quaternary ammonium cations have four organic groups attached to the nitrogen atom, they lack a hydrogen atom bonded to the nitrogen atom.
Ammonium sulfite can be prepared by the reaction of ammonia with sulfur dioxide in aqueous solution: . 2 NH 3 + SO 2 + H 2 O → (NH 4) 2 SO 3. Ammonium sulfite is produced in gas scrubbers, now obsolete, consisting of ammonium hydroxide to remove sulfur dioxide from emissions from power plants.
Other examples include the vanadous Tutton salt (NH 4) 2 V(SO 4) 2 (H 2 O) 6 and the chromous Tutton salt (NH 4) 2 Cr(SO 4) 2 (H 2 O) 6. [5] In solids and solutions, the M' 2+ ion exists as a metal aquo complex [M'(H 2 O) 6] 2+. Related to the Tutton's salts are the alums, which are also double salts but with the formula MM'(SO 4) 2 (H 2 O) 12 ...
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).