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Spontaneous process

A spontaneous process is "a physical or chemical change that occurs without the addition of energy."[1] It can also be described as a "process that will occur without any energy input from the surroundings [or a] process that will occur on its own."[2] The process can be fast or slow; "spontaneous" says nothing about its speed.[3]

A process that is capable of proceeding in a given direction, as written or described, without needing to be driven by an outside source of energy. The term is used to refer to macro processes in which entropy increases; such as a smell diffusing in a room, ice melting in lukewarm water, salt dissolving in water, and iron rusting.

The laws of thermodynamics govern the direction of a spontaneous process, ensuring that if a sufficiently large number of individual interactions (like atoms colliding) are involved then the direction will always be in the direction of increased entropy (since entropy increase is a statistical phenomenon).


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  3. ^ Chapter 10: Spontaneity, Entropy and Free Energy
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Spontaneous_process". A list of authors is available in Wikipedia.
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