Search results
Results from the WOW.Com Content Network
Calcium sulfate (or calcium sulphate) is the inorganic compound with the formula CaSO 4 and related hydrates. In the form of γ-anhydrite (the anhydrous form), it is used as a desiccant. One particular hydrate is better known as plaster of Paris, and another occurs naturally as the mineral gypsum. It has many uses in industry.
2). [6] These compounds form by oxidation of alkali metals with larger ionic radii (K, Rb, Cs). For example, potassium superoxide (KO 2) is an orange-yellow solid formed when potassium reacts with oxygen. Hydrogen peroxide (H 2 O 2) can be produced by passing a volume of 96% to 98% hydrogen and 2 to 4% oxygen through an electric discharge. [7]
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.
For elements that have multiple allotropes, the reference state usually is chosen to be the form in which the element is most stable under 1 bar of pressure. One exception is phosphorus, for which the most stable form at 1 bar is black phosphorus, but white phosphorus is chosen as the standard reference state for zero enthalpy of formation. [2]
The major use of quicklime is in the basic oxygen steelmaking (BOS) process. Its usage varies from about 30 to 50 kilograms (65–110 lb) per ton of steel. The quicklime neutralizes the acidic oxides, SiO 2, Al 2 O 3, and Fe 2 O 3, to produce a basic molten slag. [10]
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).
Polyatomic anions of the same element are named as the element name preceded by di-, tri-, etc., e.g.: O 2 2− dioxide(2−) (or peroxide as an acceptable name) C 2 2− dicarbide(2−) (or acetylide as an acceptable name) S 2 2− disulfide(2−) or sometimes as an alternative derived from a substitutive name e.g. S 2 2− disulfanediide
Calcium sulfite, or calcium sulphite, is a chemical compound, the calcium salt of sulfite with the formula CaSO 3 ·x(H 2 O). Two crystalline forms are known, the hemihydrate and the tetrahydrate, respectively CaSO 3 ·½(H 2 O) and CaSO 3 ·4(H 2 O). [2] All forms are white solids. It is most notable as the product of flue-gas desulfurization.