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The use of zinc chloride as a flux, sometimes in a mixture with ammonium chloride (see also Zinc ammonium chloride), involves the production of HCl and its subsequent reaction with surface oxides. Zinc chloride forms two salts with ammonium chloride: [NH 4] 2 [ZnCl 4] and [NH 4] 3 [ZnCl 4]Cl, which decompose on heating liberating HCl, just as ...
Zinc peroxide (ZnO 2) is a chemical compound of zinc that appears as a bright yellow powder at room temperature. It was historically used as a surgical antiseptic. More recently zinc peroxide has also been used as an oxidant in explosives and pyrotechnic mixtures. Its properties have been described as a transition between ionic and covalent ...
The reaction of zinc with water is slowed by this passive layer. When this layer is corroded by acids such as hydrochloric acid and sulfuric acid, the reaction proceeds with the evolution of hydrogen gas. [1] [9] Zn + 2 H + → Zn 2+ + H 2. Zinc reacts with alkalis as with acids.
In a compound or ion, the sum of the oxidation states equals the total charge of the compound or ion. Fluorine in compounds has OS = −1; this extends to chlorine and bromine only when not bonded to a lighter halogen, oxygen or nitrogen. Group 1 and group 2 metals in compounds have OS = +1 and +2, respectively.
The degree of dissociation in gases is denoted by the symbol α, where α refers to the percentage of gas molecules which dissociate. Various relationships between K p and α exist depending on the stoichiometry of the equation. The example of dinitrogen tetroxide (N 2 O 4) dissociating to nitrogen dioxide (NO 2) will be taken.
The order of reactivity, as shown by the vigour of the reaction with water or the speed at which the metal surface tarnishes in air, appears to be Cs > K > Na > Li > alkaline earth metals, i.e., alkali metals > alkaline earth metals, the same as the reverse order of the (gas-phase) ionization energies.
The strength of the bonds between the metal ion and water molecules in the primary solvation shell increases with the electrical charge, z, on the metal ion and decreases as its ionic radius, r, increases. Aqua ions are subject to hydrolysis. The logarithm of the first hydrolysis constant is proportional to z 2 /r for most aqua ions.
The neutron number (symbol N) is the number of neutrons in a nuclide. Atomic number (proton number) plus neutron number equals mass number : Z + N = A . The difference between the neutron number and the atomic number is known as the neutron excess: D = N − Z = A − 2 Z .