Search results
Results From The WOW.Com Content Network
Chemical reactions are usually characterized by a chemical change, and they yield one or more products, which usually have properties different from the reactants. Reactions often consist of a sequence of individual sub-steps, the so-called elementary reactions , and the information on the precise course of action is part of the reaction ...
The magnitude of the equilibrium constant depends on the Gibbs free energy change for the reaction. [2] So, when the free energy change is large (more than about 30 kJ mol −1), the equilibrium constant is large (log K > 3) and the concentrations of the reactants at equilibrium are very small. Such a reaction is sometimes considered to be an ...
The enthalpy of a chemical system is essentially its energy. The enthalpy change ΔH for a reaction is equal to the heat q transferred out of (or into) a closed system at constant pressure without in- or output of electrical energy. Heat production or absorption in a chemical reaction is measured using calorimetry, e.g. with a bomb calorimeter.
According to the IUPAC, an exothermic reaction is "a reaction for which the overall standard enthalpy change ΔH⚬ is negative". [4] Some examples of exothermic process are fuel combustion, condensation and nuclear fission, [5] which is used in nuclear power plants to release large amounts of energy. [6]
In physics, chemistry, and other related fields like biology, a phase transition (or phase change) is the physical process of transition between one state of a medium and another. Commonly the term is used to refer to changes among the basic states of matter: solid, liquid, and gas, and in rare cases, plasma.
In a reversible reaction, chemical equilibrium is reached when the rates of the forward and reverse reactions are equal (the principle of dynamic equilibrium) and the concentrations of the reactants and products no longer change. This is demonstrated by, for example, the Haber–Bosch process for combining nitrogen and hydrogen to produce ammonia.
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.
Example of a reduction–oxidation reaction between sodium and chlorine, with the OIL RIG mnemonic [1] 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]