Question

What is the first law of thermodynamics for a closed system?

Answer 1

We need to know that in chemical thermodynamics it discusses the interrelation between heat and work in a chemical reaction. The chemical thermodynamics is explained on the basis of two laws of thermodynamics. That is, the first law of thermodynamics and second law of dynamics. According to thermodynamics, a closed system can exchange energy in the form of heat and work.

Complete answer:
The first law of thermodynamics for a closed system states that, in the time of an interaction between surroundings with the system, the amount of energy lost by the surroundings is equal to the amount of energy absorbed by the system. In the case of a closed system, it can exchange the energy in the term of heat and work with the surroundings but can’t exchange the matter with the surroundings. But for the open system, it can exchange both matter and energy. In the case of an isolated system, it cannot exchange any of the matter, work and heat with the surroundings. The formula of the closed system can be written as,
$\Delta E = \Delta K.E + \Delta P.E + \Delta U$
$= Q - W$
The energy is transferred in the form of heat and work between the system and surroundings and it develops the change in the total energy of the system.

Note:
According to the first law of thermodynamics, the amount of energy absorbed by the system is equal to the amount of energy lost by the surrounding during the time of interaction between system and the surrounding. And the closed system will not exchange the energy with the surroundings. And this law is also applicable for the open system. In an open system, there is an exchange of both energy and mass.