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My understanding is that if a reaction takes place, either entropy of the system must rise, or energy must be released from the system as heat, or both. (Citation: paraphrasing from The Vital Question, by Nick Lane). But plant life seems to both decrease entropy, and absorb (not release) energy from its surroundings, by way of photosynthesis. How is this adhering to the constraint that the change in Gibbs free energy in a reaction must be negative?

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    $\begingroup$ You are not looking at a closed system (energywise). Which would be necessary to be able to make such observations. $\endgroup$ – Chris Jun 26 '16 at 21:20
  • $\begingroup$ Your title was nonsense as it stood (as was your last sentence). It mentioned free energy, rather than free energy change, and did not indicate what it referred to. I have altered it in accordance with your actual question, but please take more care in future. Titles are used for indexing and are important. $\endgroup$ – David Jun 26 '16 at 22:32
  • $\begingroup$ Possible duplicate (or at least quite related) to question on entropy and evolution $\endgroup$ – David Jun 26 '16 at 22:39
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    $\begingroup$ "My understanding is that if a reaction takes place, either entropy of the system must rise, or energy must be released from the system as heat, or both."... No, that is if a reaction takes place spontaneously. You can perform work on the system to move it against the energy gradient. That's what the second law of thermodynamics says. In photosythesis, the energy of the light is indirectly used to perform that work. $\endgroup$ – WYSIWYG Jun 27 '16 at 5:13

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