Search results
Results From The WOW.Com Content Network
The standard state of a material (pure substance, mixture or solution) is a reference point used to calculate its properties under different conditions.A degree sign (°) or a superscript Plimsoll symbol (⦵) is used to designate a thermodynamic quantity in the standard state, such as change in enthalpy (ΔH°), change in entropy (ΔS°), or change in Gibbs free energy (ΔG°).
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).
This is an accepted version of this page This is the latest accepted revision, reviewed on 4 February 2025. This article is about the chemical element. For other uses, see Iodine (disambiguation). Chemical element with atomic number 53 (I) Iodine, 53 I Iodine Pronunciation / ˈ aɪ ə d aɪ n, - d ɪ n, - d iː n / (EYE -ə-dyne, -din, -deen) Appearance lustrous metallic gray solid ...
The data below tabulates standard electrode potentials (E°), in volts relative to the standard hydrogen electrode (SHE), at: Temperature 298.15 K (25.00 °C; 77.00 °F); Effective concentration (activity) 1 mol/L for each aqueous or amalgamated (mercury-alloyed) species; Unit activity for each solvent and pure solid or liquid species; and
Compounds with iodine in formal oxidation state −1 are called iodides. In everyday life, iodide is most commonly encountered as a component of iodized salt , which many governments mandate. Worldwide, iodine deficiency affects two billion people and is the leading preventable cause of intellectual disability .
Tin(II) iodide, also known as stannous iodide, is an ionic tin salt of iodine with the formula SnI 2. It has a formula weight of 372.519 g/mol. It is a red to red-orange solid. Its melting point is 320 °C, and its boiling point is 714 °C. [1] Tin(II) iodide can be synthesised by heating metallic tin with iodine in 2 M hydrochloric acid. [2 ...
It has a cubic crystal structure with the space group Pa 3 (space group no. 205), the lattice parameter a = 1226 pm and eight formula units per unit cell. [4] This corresponds approximately to a cubic close packing of iodine atoms in which 1/8 of all tetrahedral gaps are occupied by tin atoms. This leads to discrete tetrahedral SnI 4 molecules. [5]
The iodine clock reaction is a classical chemical clock demonstration experiment to display chemical kinetics in action; it was discovered by Hans Heinrich Landolt in 1886. [1] The iodine clock reaction exists in several variations, which each involve iodine species (iodide ion, free iodine, or iodate ion) and redox reagents in the presence of ...