State the first law of thermodynamics. Express it in mathematical form
Answers
Answer:
The mathematical expression which is used to represent the first law of thermodynamics is ΔE = q-w, where ΔE refers to the internal energy change of the system when ‘w’ amount of work is done by the system when it absorbs ‘q’ amount of heat and carries out ‘w’ amount of work.
Explanation:
the first law of thermodynamics is a version of the law of conservation of energy, adapted for thermodynamic processes, distinguishing two kinds of transfer of energy, as heat and as thermodynamic work, and relating them to a function of a body's state, called Internal energy. The law of conservation of energy states that the total energy of an isolated system is constant; energy can be transformed from one form to another, but can be neither created nor destroyed
According to the first law of thermodynamics, during any transformation, there is conservation of energy.
In the case of closed thermodynamic systems, it is stated as follows:
"During any transformation of a closed system, the variation of its energy is equal to the quantity of energy exchanged with the external environment, by thermal transfer (heat) and mechanical transfer (labor). "
ΔQ = ΔU + W
where,
Q = Heat supplied to system
U = Increase in internal energy
W = Work done by system
The variation of the energy of a system which undergoes a transformation can be expressed according to the following relation:
ΔE = ΔU + ΔEc + ΔEp = W + Q
ΔE = the sum of the different energy variations of the system.
ΔU = increase in internal energy
ΔEc = the variation of the macroscopic kinetic energy of the system
ΔEp = the variation of the potential energy of the system
ΔW = Work done by system
ΔQ = Heat supplied to a system