Entropy of expansion and mixing

In the free myosin and ATP there is considerable binding of water molecules, but when the complex is formed there is a certain amount of charge neutralization and therefore a reduction in the electric field and a decrease in the binding of water molecules. Thus there is an entropy increase, and this plays a significant role in the mechanism of muscular contraction. 

The entropy change which occurs on the contraction of a muscle is also of interest. 

We have seen that if one mole of an ideal gas performs a reversible isothermal expansion at temperature T, from volume Vi to volume Vj, the heat absorbed is 

The entropy increase, AS, is the heat absorbed divided by the constant temperature T  

This entropy increase is known as the entropy of mixing. There is an increase in entropy because the mixed state is more probable than the unmixed state. 

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