Can you have negative entropy

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We know that the entropy is zero for reversible processes and always positive for irreversible processes. Can there exist a system which may have negative entropy? In the zero-entropy case, the object is a perfect crystal at zero temperature, which has only one possible microstate. Thus, the above definition is made possible by the Third Law of Thermodynamics.

Any other situation has more than one possible microstate, so the entropy must be greater than zero. I think what you mean is that the entropy doesn't change for reversible processes, but increases for irreversible processes.

In this sense your question would be if the entropy of a system can decrease. Yes, absolutely! The entropy can decrease for a system that is not closed. For example, Earth receives the solar energy prom the Sun and dissipates it into space as heat. The entropy of the whole closed system Sun, Earth, and space always increases. However, the entropy on Earth alone can indeed decrease.

Entropy is often referred to as a measure of chaos, so order would be the opposite of entropy. In this sense biological life and evolution represent a highly organized matter and therefore a low entropy. Such a reduction of the entropy as the emergence of life and its evolution on Earth was possible exactly because Earth alone is not a closed system, but a conduit of a tremendous entropy increase of the solar energy dissipating as heat.

Without this constant entropy increase, life on Earth would be impossible. Re: negative entropy Post by Srbui Azarapetian 2C » Sun Feb 04, pm The change in entropy can be negative, and when this is the case, you can think of it as a system becoming more ordered.

An example would be of condensation, in the transition from a gas high entropy state to a liquid low entropy state. Because of this, I don't think there is any way that you'd be able to have a system with a negative entropy.

Re: negative entropy Post by Ridhi Ravichandran 1E » Mon Feb 05, am There is no such thing as negative entropy, but a negative change in entropy exists. For example, a reaction that condenses from a gas to liquid would have a negative delta S because the liquid would occupy less possible states than the gas due to the decrease in temperature and volume.

The third law of thermodynamics holds that "The entropies of all perfect crystals approach zero as the absolute temperature approaches zero. What Are Causes of Chemical Reactions? Examples of Applied Science. What Are Examples of an Increase in Entropy? How to Calculate Heat of Sublimation. What Is Gibbs Free Energy? What is an Endergonic Reaction? Thermal Dynamics Experiments for Kids.