Scientific Definition of a Closed System in Thermodynamics

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By
Anne Marie Helmenstine, Ph.D.
Chemistry Expert
  • Ph.D., Biomedical Sciences, University of Tennessee at Knoxville
  • B.A., Physics and Mathematics, Hastings College
Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels.
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Anne Marie Helmenstine, Ph.D.
Updated April 09, 2019

A closed system is a concept used in thermodynamics (physics and engineering) and in chemistry. It differs from an isolated system.

Closed System Definition

A closed system is a type of thermodynamic system where mass is conserved within the boundaries of the system, but energy is allowed to freely enter or exit the system.

In chemistry, a closed system is one in which neither reactants nor products can enter or escape, yet which allows energy transfer (heat and light). A closed system may be used for experiments where temperature isn't a factor.

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Helmenstine, Anne Marie, Ph.D. "Scientific Definition of a Closed System in Thermodynamics." ThoughtCo, Feb. 16, 2021, thoughtco.com/definition-of-closed-system-604929. Helmenstine, Anne Marie, Ph.D. (2021, February 16). Scientific Definition of a Closed System in Thermodynamics. Retrieved from https://www.thoughtco.com/definition-of-closed-system-604929 Helmenstine, Anne Marie, Ph.D. "Scientific Definition of a Closed System in Thermodynamics." ThoughtCo. https://www.thoughtco.com/definition-of-closed-system-604929 (accessed October 21, 2021).