Definition
In chemistry, the activity of a species is a measure of its effective concentration, as distinct from its concentration. This is, by convention, usually presented as a unitless value. Activity can be affected by factors such as pressure, temperature, and the presence of other solutes. The difference in value between concentration and activity is due to the fact that molecules in solution often display nonideal behavior due to molecular interactions. In the gas phase, activity is called fugacity.
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Cleaves, H.J. (2022). Activity. In: Gargaud, M., et al. Encyclopedia of Astrobiology. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-27833-4_27-4
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DOI: https://doi.org/10.1007/978-3-642-27833-4_27-4
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Publisher Name: Springer, Berlin, Heidelberg
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