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The definition of the Gibbs function is = + where H is the enthalpy defined by: = +. Taking differentials of each definition to find dH and dG, then using the fundamental thermodynamic relation (always true for reversible or irreversible processes): = where S is the entropy, V is volume, (minus sign due to reversibility, in which dU = 0: work other than pressure-volume may be done and is equal ...
For example, oxygen makes up about 8 / 9 of the mass of any sample of pure water, while hydrogen makes up the remaining 1 / 9 of the mass: the mass of two elements in a compound are always in the same ratio. Along with the law of multiple proportions, the law of definite proportions forms the basis of stoichiometry. [1]
Free Steam Tables Online calculator based on IAPWS-IF97 FACT-Web programs Various on-line tools for obtaining thermodynamic data and making equilibrium calculations. Mol-Instincts A chemical database based on Quantum Mechanics and QSPR, providing thermodynamic properties for millions of compounds.
For substitutional solid solutions, the Hume-Rothery rules are as follows: The atomic radius of the solute and solvent atoms must differ by no more than 15%: [1] % = % %. The crystal structures of solute and solvent must be similar.
Subscripts "1" and "2" denote symmetry and antisymmetry, respectively, with respect to a nonprincipal rotation axis. Higher numbers denote additional representations with such asymmetry. Single prime ( ' ) and double prime ( '' ) superscripts denote symmetry and antisymmetry, respectively, with respect to a horizontal mirror plane σ h , one ...
Alchemical symbols were used to denote chemical elements and compounds, as well as alchemical apparatus and processes, until the 18th century. Although notation was partly standardized, style and symbol varied between alchemists.
Fe (s) + H 2 SO 4 (l) → FeSO 4 (aq) + H 2 (g) There is some ambiguity at the borderlines between the groups. Magnesium , aluminium and zinc can react with water, but the reaction is usually very slow unless the metal samples are specially prepared to remove the surface passivation layer of oxide which protects the rest of the metal.
Because the S 2− anion has a subscript of 2 in the formula (giving a 4− charge), the compound must be balanced with a 4+ charge on the Pb cation (lead can form cations with a 4+ or a 2+ charge). Thus, the compound is made of one Pb 4+ cation to every two S 2− anions, the compound is balanced, and its name is written as lead(IV) sulfide.