state first law of thermodynamics
Answers
The first law, also known as Law of Conservation of Energy, states that energy cannot be created or destroyed in an isolated system. The second law of thermodynamics states that the entropy of any isolated system always increases.
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