Search results
Results from the WOW.Com Content Network
In thermodynamics, an exothermic process (from Ancient Greek έξω (éxō) 'outward' and θερμικός (thermikós) 'thermal') [1] is a thermodynamic process or reaction that releases energy from the system to its surroundings, [2] usually in the form of heat, but also in a form of light (e.g. a spark, flame, or flash), electricity (e.g. a ...
The reduction of iron (III) oxide by aluminium releases sufficient heat to yield molten iron. In thermochemistry, an exothermic reaction is a "reaction for which the overall standard enthalpy change Δ H ⚬ is negative." [1][2] Exothermic reactions usually release heat. The term is often confused with exergonic reaction, which IUPAC defines as ...
A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. [1] When chemical reactions occur, the atoms are rearranged and the reaction is accompanied by an energy change as new products are generated. Classically, chemical reactions encompass changes that only involve the positions ...
Hammond's postulate. Hammond's postulate (or alternatively the Hammond–Leffler postulate), is a hypothesis in physical organic chemistry which describes the geometric structure of the transition state in an organic chemical reaction. [1] First proposed by George Hammond in 1955, the postulate states that: [2]
The molecule leaves the surface. Hydrogenation is a chemical reaction between molecular hydrogen (H 2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to reduce or saturate organic compounds.
The law states that the total enthalpy change during the complete course of a chemical reaction is independent of the sequence of steps taken. [1] [2] Hess' law is now understood as an expression of the fact that the enthalpy of a chemical process is independent of the path taken from the initial to the final state (i.e. enthalpy is a state ...
Redox (/ ˈ r ɛ d ɒ k s / RED-oks, / ˈ r iː d ɒ k s / REE-doks, reduction–oxidation [2] or oxidation–reduction [3]: 150 ) is a type of chemical reaction in which the oxidation states of the reactants change. [4] Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a ...
A single-displacement reaction, also known as single replacement reaction or exchange reaction, is an archaic concept in chemistry. It describes the stoichiometry of some chemical reactions in which one element or ligand is replaced by atom or group. [1][2][3] It can be represented generically as: where either. A {\displaystyle {\ce {A}}}