Spontanreaktion

Spontanreaktion is a German term that translates to spontaneous reaction in English. It refers to a chemical or physical process that occurs naturally without external intervention once initiated. In thermodynamics, a spontaneous process is one that has a negative change in Gibbs free energy (ΔG < 0) under constant temperature and pressure. This indicates that the process is thermodynamically favorable and will proceed in the forward direction without continuous energy input.

The spontaneity of a reaction is determined by two main factors: enthalpy change (ΔH) and entropy change (ΔS). A reaction that releases heat (exothermic, ΔH < 0) tends to be spontaneous, as does a reaction that increases the disorder or randomness of the system (increase in entropy, ΔS > 0). The Gibbs free energy equation, ΔG = ΔH - TΔS, combines these factors, where T is the absolute temperature. If ΔG is negative, the reaction is spontaneous.

It is important to distinguish between spontaneity and reaction rate. A spontaneous reaction may be very slow if the activation energy is high. Conversely, a non-spontaneous reaction can be made to occur if sufficient energy is supplied, such as through electrolysis. Examples of spontaneous processes include the rusting of iron, the dissolution of salt in water, and the expansion of a gas into a vacuum. Understanding spontaneity is crucial in predicting the feasibility of chemical reactions and designing chemical processes.