The document provides an overview of thermodynamics, defining it as the science of energy transfers and their effects on systems, and outlines its four laws. It discusses the characteristics of thermodynamic systems, including closed, open, and isolated systems, along with the concepts of state and properties, which are classified into intensive and extensive types. Additionally, the document explains thermodynamic equilibrium and quasi-static processes, emphasizing the conditions required for equilibrium and the nature of reversible processes.

1. PREPARED BY: DHAVAL

2.  Introduction
 Thermodynamics System
 State and Property
 Thermodynamic Equilibrium
 Quasi-static Process

3.  What is THERMODYNAMICS?
 Thermodynamics is the science which deals with energy transfers and its effect on
the condition of a system.
 This study of science has led to the various laws of thermodynamics.
1. The zeroth law – concept of equality of temperature, thermal equilibrium.
2. The first law – law of conservation of energy, internal energy.
3. The second law – direction of flow of heat, concept of entropy.
4. The third law – absolute zero of entropy.

4.  A thermodynamic system is defined as a
fixed mass in a region of space under
consideration to analyse a problem.
 The system is identified by a boundary
drawn around the system where the
boundary can be classified as 1) rigid or
flexible and 2) real or imaginary.
 Everything external to the system is called
surroundings.
 Universe is the sum system and
surroundings.

5.  Classification of Thermodynamic Systems:
1. Closed system – no mass transfer, only energy transfer.
2. Open system – both mass and energy transfer across the boundary.
3. Isolated system – no mass or energy transfer takes place.

6.  State – the identification of the system by observable or measurable
characteristics is called the state of the system.
 Property – thermodynamic co-ordinates representing a system are called
properties of the system.
 Properties are classified as,
1. Intensive properties – independent of mass e.g. pressure, temperature,
viscosity, etc.
2. Extensive properties – depends on mass e.g. length, volume, all forms of energy,
entropy.

7.  A system is said to be in thermodynamic equilibrium which is incapable of any
change of its macroscopic properties and is in complete balance with its
surroundings.
 A system will be in thermodynamic equilibrium if it satisfies the condition of
mechanical, thermal and chemical equilibrium.
 Mechanical equilibrium – no unbalanced forces
 Thermal equilibrium – uniform temperature
 Chemical equilibrium – absence of any chemical reaction

8.  Quasi means almost slow or infinitely slow.
 A quasi-static process is defined as a process in which the properties of the system
depart infinitesimally or extremely small from the thermodynamic equilibrium
path.
 A quasi-static process is also called a reversible process.
 It is a succession of equilibrium states.