Why does entropy increase stability

Search for:. The Second Law of Thermodynamics Learning Outcomes Understand how the second law of thermodynamics applies to biological systems.

Try It Yourself Set up a simple experiment to understand how energy is transferred and how a change in entropy results. Take a block of ice. This is water in solid form, so it has a high structural order. This means that the molecules cannot move very much and are in a fixed position. As a result, the entropy of the system is low. Allow the ice to melt at room temperature. What is the state of molecules in the liquid water now? How did the energy transfer take place?

Is the entropy of the system higher or lower? Heat the water to its boiling point. Most of these final states look disordered. Diffusion is therefore an entropically favorable process that brings an ordered system into a disordered one. Additional remark. I find statements like "entropy drives the system towards a particular state" to be somewhat misleading, because they imply that entropy behaves like a force.

But entropy, as we've seen, is really just statistics. Entropy just happens — as long as the universe isn't frozen solid, things will always be moving around, and that movement tends to introduce randomness more than it tends to introduce order.

Consider a deck of cards. Shuffle it. Is it perfectly sorted? The number of different available states e. The same principle applies everywhere else in the universe: in the face of random microscopic state changes, the odds are stacked in favour of mishmash and against macroscopic "order" appearing by mere chance — and overwhelmingly so.

Do not think of entropy as 'disorder' as this is misleading, better is that it is a 'measure of disorder' but this is equally vague. It is better to think of entropy as the number of ways that 'particles' or quanta say vibrational or rotational quanta in a molecule can be placed among the various energy levels available. Thus at zero energy all the particles are in their lowest levels and there is only one way of doing this and so entropy is zero.

As the energy is increased then more levels can become populated and so there are many different ways of populating all the energy level this and so the entropy is increased. Think of the calculations, usually given as examples in calculating probability, where one has to find the number of ways of placing identical balls into bags. If we look at why a chemical bond occurs maybe that might shed light on to this question.

If we take diatomic hydrogen which has one electron from each hydrogen, the question arises why do two nuclei come together to form a bond since Coloumbic forces are increased. And the answer is because the electrons have a larger volume to exist in as they will be able to exchange between nuclei I'm referring to the exchange integral. Thus we can summarize that a chemical bond occurs due to purely entropic reasons and as a result the energy of the system is decreased.

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Active 1 month ago. Viewed 58 times. Improve this question. UnrulyTank UnrulyTank 5 5 bronze badges. It decreases, not increases, with increasing entropy. Then read the discussions about the Gibbs free energy on this site; they address all of these points.

Add a comment. Active Oldest Votes. Improve this answer. Osmium Osmium 11 11 bronze badges. Post by cgarcia » Mon Jan 20, am.

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