# THERMODYNAMICS | STATE AND EQULIBRIUM

STATE AND EQULIBRIUM

When no change occurs in the system properties, at this point all the properties can be measured or calculated throughout the entire system. The properties at this static conduction describe the state of the system. At a given state, all the properties of a system have fixed value. If the value of even one property changes, the state will change to a different one. The word equilibrium implies a state of balance. In an equilibrium state, there are no unbalanced potentials/ forces within the system. When a system is isolated from its surroundings, the system experience no change in it. There are mainly three types of equilibrium, and a system is not in thermodynamics equilibrium unless the conditions of all the three relevant types of equilibrium are satisfied;

A. Thermal equilibrium . Temperature  should be same throughout the system.

B. Mechanical equilibrium. Unbalanced forces should be absent. change to pressure.

C. Chemical equilibrium. No chemical reaction and mass transfer occur.

Change in state: Thermodynamics system undergoes changes due to flow of mass and energy. The mode in which the change in the state of a system take place is known as process such as isobaric (constant pressure) process, isochoric(constant volume) process, isothermal (constant temperature) process, adiabatic (state entropy )process. The path is the loci of series of state changes from initial state to final state during a process. The changes in state and path of a process are. The thermodynamics cycle refers to the sequence of process in which initial and final states of the system are same. For ex. otto cycle, Diesel cycle, joule cycle, Rankine cycle, Carnot cycle, etc. have identical initial and final states.

Question

1. what is an equilibrium state ?

In thermodynamics the concept of equilibrium includes not only a balance of forces, but also a balance of other influencing factors, such as thermal equilibrium pressure equilibrium, phase equilibrium, etc.

2. What is meant by state in thermodynamics ?

At any instant of time, the condition of a system is called a state. The state at a given instant of time is defined by the properties of the system such as pressure, volume, temperature etc.

3. What are three states of equilibrium ?

They are three states of equilibrium

A. Thermal equilibrium . Temperature  should be same throughout the system.

B. Mechanical equilibrium. Unbalanced forces should be absent. change to pressure.

C. Chemical equilibrium. No chemical reaction and mass transfer occur.

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