Question

what does the first law of thermodynamics state

Answer 1

The first law of thermodynamic states that heat is a form of energy and thermodynamic processes are therefore, subject to the principle of conservation of energy. This means heat cannot be created nor destroyed.

Answer 2

: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