Timeline for Difference between spontaneous and irreversible process?
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18 events
| when toggle format | what | by | license | comment | |
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| Jun 25, 2023 at 13:05 | answer | added | The Quark | timeline score: 0 | |
| Jun 25, 2023 at 11:44 | comment | added | The Quark | @ChetMiller I see. Thank you for the explanation. | |
| Jun 25, 2023 at 11:27 | comment | added | Chet Miller | A reversible reaction is one in which, if you start out only with reactants present, the reaction will proceed in the forward directions, and the equilibrium state will feature both reactants and products; and, if you start out only with products, the reaction will proceed in reverse and the equilibrium state will feature both reactants and products. On the other hand, a reversible process is one in which, if the initial state of a system is A and the final state is B, you can return both system and surroundings from state B to state A without affecting any other entity. | |
| Jun 25, 2023 at 11:19 | comment | added | The Quark | @ChetMiller In chemistry, I have seen some use "irreversible reaction" to mean "total reaction", which for me are two different things. At the molecular level, everything is reversible, so irreversible can only be a "coarse-grained", thermodynamic concept. A (bulk) reaction can go to equilibrium, but if the reacting system is initially out-of-equilibrium, the transformation (reaction) is irreversible in the sense that entropy is created. So I see no difference, irrespective of the context. | |
| Jun 25, 2023 at 11:09 | comment | added | Chet Miller | @Quark You first. What are your thoughts on the definitions of these concepts? | |
| Jun 24, 2023 at 17:58 | comment | added | The Quark | @ChetMiller What do you mean by "reversible and irreversible have different context with regard to chemical reactions than with regard to non-chemical processes"? What different meanings do these terms have in those different contexts? | |
| Apr 28, 2023 at 17:18 | history | became hot network question | |||
| Apr 28, 2023 at 15:28 | comment | added | Ján Lalinský | > "both processes increase universe's entropy." Don't say this. Nobody knows whether Universe has meaningful thermodynamic entropy and whether it increases or decreases (we can't do thermodynamic experiments on the Universe, and no heat exchange with the Universe has been ever observed). It's better to say those processes generate entropy. | |
| Apr 28, 2023 at 15:18 | answer | added | hyportnex | timeline score: 5 | |
| Apr 28, 2023 at 15:10 | comment | added | Quillo | @JohnDavies the "shape" of the relevant free energy landscape is important. Spontaneous -> after the free energy barrier, the new equilibrium is at a lower free energy (vice-versa for non-spontanous). See: differencebetween.com/… (both spontaneous and non-spontaneous are typically irreversible unless they always go through a sequence of equilibrium states). | |
| Apr 28, 2023 at 11:09 | answer | added | Themis | timeline score: 8 | |
| Apr 28, 2023 at 10:34 | comment | added | Chet Miller | For such a system, I would regard spontaneous as the subset of irreversible processes over which you exert no control while they are occurring. | |
| Apr 28, 2023 at 10:29 | comment | added | John Davies | @ChetMiller Yes, by irreversible I mean processes in which the entropy of the universe increases and reversible processes keeps the universe's entropy constant. | |
| Apr 28, 2023 at 10:22 | comment | added | Chet Miller | The terms reversible and irreversible have different context with regard to chemical reactions than with regard to non-chemical processes. | |
| Apr 28, 2023 at 9:51 | history | edited | John Davies | CC BY-SA 4.0 |
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| Apr 28, 2023 at 8:37 | history | edited | Qmechanic♦ | CC BY-SA 4.0 |
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| Apr 28, 2023 at 8:07 | history | edited | Qmechanic♦ |
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| Apr 28, 2023 at 7:07 | history | asked | John Davies | CC BY-SA 4.0 |