First law of thermodynamics has some limitations. Before going to know about that, we need to remind what are the different forms of first law of thermodynamics.
First law of thermodynamics is also known as law of conservation of energy.
“Energy neither be created nor be destroyed, but it can be changed from one form to another”.
“It is impossible to construct a perpetual motion machine of first kind that can work without consuming any form of energy”.
” Total energy of an isolated system remains constant.”
The net energy change in a closed system is equal to the sum of heat absorbed and work done on the system by the system”.
The mathematical form of first law of thermodynamics is, Δ U = Q + W.
Where:
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= Change in internal energy of system
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= Heat absorbed or released
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W = Work done by or on the system.
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Limitations of first law of thermodynamics : First law of thermodynamics does not give any information about the direction in which flow of energy takes place. It also does not explain why the naturally occurring (spontaneous) processes are Irreversible in nature. Disla does not contradict the existence of 100% efficient heat engine. We may observe some more limitations of this, this law does not explain why some chemical reactions do not proceed to completion. It fails to answer why the heat energy does not flow from cold body( low temperature) to heart body (high temperature ). First love thermodynamics explain one form of energy is converted into another but it could not explain how much one form of energy is converted into another form.