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  2. Electron affinity - Wikipedia

    en.wikipedia.org/wiki/Electron_affinity

    Electron capture for almost all non-noble gas atoms involves the release of energy [4] and thus is exothermic. The positive values that are listed in tables of E ea are amounts or magnitudes. It is the word "released" within the definition "energy released" that supplies the negative sign to Δ E .

  3. Enthalpy change of solution - Wikipedia

    en.wikipedia.org/wiki/Enthalpy_change_of_solution

    The equilibrium, between the gas as a separate phase and the gas in solution, will by Le Châtelier's principle shift to favour the gas going into solution as the temperature is decreased (decreasing the temperature increases the solubility of a gas). When a saturated solution of a gas is heated, gas comes out of the solution.

  4. Thermometric titration - Wikipedia

    en.wikipedia.org/wiki/Thermometric_titration

    It is postulated that the breakpoint is revealed by the difference in reaction enthalpies between the formation of the Cu-EDTA complex, and that for the formation of the Cu-amine complex. Fig. 16. Thermometric EDTA titration determination of trace Cu(II) by Mn(II) catalysis of exothermic reaction between hydrogen peroxide and polyhydric phenol.

  5. Exothermic reaction - Wikipedia

    en.wikipedia.org/wiki/Exothermic_reaction

    In thermochemistry, an exothermic reaction is a "reaction for which the overall standard enthalpy change ΔH⚬ is negative." [ 1 ] [ 2 ] Exothermic reactions usually release heat . The term is often confused with exergonic reaction , which IUPAC defines as "... a reaction for which the overall standard Gibbs energy change Δ G ⚬ is negative."

  6. Chemical reaction - Wikipedia

    en.wikipedia.org/wiki/Chemical_reaction

    G: free energy, H: enthalpy, T: temperature, S: entropy, Δ: difference (change between original and product) Reactions can be exothermic, where ΔH is negative and energy is released. Typical examples of exothermic reactions are combustion, precipitation and crystallization, in which ordered solids are formed from disordered gaseous or liquid ...

  7. Thermal decomposition - Wikipedia

    en.wikipedia.org/wiki/Thermal_decomposition

    This is because stronger bonds form between atoms towards the top of the reactivity series, and strong bonds are difficult to break. For example, copper is near the bottom of the reactivity series, and copper sulfate (CuSO 4 ), begins to decompose at about 200 °C (473 K; 392 °F), increasing rapidly at higher temperatures to about 560 °C (833 ...

  8. Exothermic process - Wikipedia

    en.wikipedia.org/wiki/Exothermic_process

    An exothermic thermite reaction using iron(III) oxide. The sparks flying outwards are globules of molten iron trailing smoke in their wake. Some examples of exothermic processes are: [14] Combustion of fuels such as wood, coal and oil/petroleum; The thermite reaction [15] The reaction of alkali metals and other highly electropositive metals ...

  9. Hess's law - Wikipedia

    en.wikipedia.org/wiki/Hess's_law

    A representation of Hess's law (where H represents enthalpy) Hess's law of constant heat summation, also known simply as Hess's law, is a relationship in physical chemistry and thermodynamics [1] named after Germain Hess, a Swiss-born Russian chemist and physician who published it in 1840.