The driving force is the increase of entropy in the entire universe.
The explanation with regard to Gibbs energy.
I have described several times that the change in the system becomes a spontaneous process, due to the negative value of Gibbs energy change.
I feel that it is necessary to explain with regard to Gibbs energy, so I will explain with regard to it.
The explanation with regard to entropy.
Prior to the discussion of Gibbs energy, it is needed to explain with regard to entropy.
There are two kinds of properties of matter in this world.
One is the "extensive property" and another is the "intensive property".
The property which depend on its quantity is called "extensive property" and property which dosen't depend on its quantity is called "intensive property".
Mass,volume,area,energy,charge,etc. have the extensive property. Temperature and denssity have the intensive property.
However the events in this world are often discussed with probability, the probability itself doesn't belong to any of the above.
Mr.Boltzmann succeeded in the conversion of the probability value into the value with extensive property.
The entropy is the product of the converted value by the Boltzmann's constant.
The Boltzmann's constan is the appropriate value to relate the converted value and the energy.
However the entropy is not the probability value as you know, the probability value and the entropy are deeply related.
There is the relationship in which the entropy of the system increases due to the high probability value of the system.
Therefore, judging about probability allows us to make the relative judgments regarding entropy(S).
In addition to the entropy(S) derived by the statistical methods such as probability, there is the entropy (S) derived from the amount of heat.
The appropriate constant(the Boltzmann's constant) is defined in the former so that the two coincide.
The entropy (s) derived from the amount of heat is the value obtained by dividing the amount of heat by the absolute temperature.
When two objects with different temperatures come into contact, a hot object loses some amount of heat and a cold object gains the same amount of heat to reach to the same temperature.
Since the increase in entropy of the latter is larger than the decrease in entropy of the former, as an overall the entropy is increasing.
The entropy (S) of the state determined by such spontaneous phenomena always increases.
It should be emphasized here that the spontaneous phenomenon has the important significance.
When a spontaneous phenomenon occurs some kind of the driving force is at work.
The idea is that the driving force is sought in the increasing entropy (S) of entire universe.
This is expressed by the following equation as the second law of thermodynamics which is a versatile law.
ΔSuniv ＝ ΔSsys ＋ ΔSsurr ≧ 0
The value of entropy(S) of the entire universe increases with the spontaneous process.
System represents the inside of system,
surrounding represents the sorrounding environment of system,
and the equal sign holds only in reversible processes.
It's ameliorate bettet my life when I am always solving problems in contact with the universe
but it's hard to calculate the whole universe all time so I want to do something with regard to it.
