Thermodynamics deals with energy transfer through heat and work and how it affects systems. A system is separated from its surroundings by a boundary. Systems can be closed, open, or isolated depending on if mass and energy transfer occurs. Properties of a system include temperature, pressure, volume and can be intensive or extensive. The first law of thermodynamics states that heat transfer equals work transfer during a thermodynamic cycle for a closed system. It does not specify the direction of heat and work transfers or that heat can be fully converted to work.

1. FUNDAMENTAL OF THERMODYNAMICS
• Thermodynamics is the branch of science dealing with energy
transfer in the form of heat and work & effect of energy transfer
on the properties of the system.

2. BASIC CONCEPTS
• Pure Substance: A pure substance is a single substance
which retains an unvarying molecular structure during the
process of energy transfer.
• Thermodynamic System : A thermodynamic system is
defined as a region in space or a quantity of matter upon
which attention is focussed for the study of work & heat
transfer.

3. • Surrounding: Everything outside the system which has
direct bearing on its behavior is called as surrounding .
• Boundary: The system is seperated from the surrounding
by the system boundary.
• Universe: It consist of system and surrounding.

4. CLASSIFICATION OF SYSTEMS
• Closed System: In this system mass remains constant and
energy(heat and work) can transfer through the boundary in or out.
• Open System: In this system both mass and energy transfer takes
place.

5. • Isolated System: In this system neither energy nor mass
transfer takes place between system and surrounding.

6. PROPERTY OF ASYSTEM
• Any characteristic of the system which can be observed or measured
is called as property of the system.e.g. pressure,temperature, volume
• Intensive properties: The properties which are not dependant on
mass/size of the system are called as Intensive properties. e.g.
pressure,temperature,density
• Extensive properties: The properties which are dependant on
mass/size of the system are called as extensive properties.
e.g.mass,volume,energy

8. • Density: It is defined as the mass of the unit volume.
ρ=m/v
• Specific Volume: The volume occupied per unit mass is
known as Specific volume.
Vs=V/m
• Specific Gravity: It is the ratio of density of the substance
to the density of reference substance.
• Pressure: Pressure is defined as force per unit area.
p=F/A
• Temperature: It is quantitative measurement of degree
of hotness or intensity of heat of body.

9. • State: Each unique condition of a system is called a state.
A system is said to be at steady state if none of its
properties changes.
• Path of change of state: When a system passes through
the continuous series of equilibrium states during a
change of state, it is path of change of state.
• Process: A process is said to be occurred when a system
undergoes a change in state.

10. • Thermodynamic Cycle: If number of processes in
sequence brings back the system to its initial state, the
system is said to execute a cycle.

11. • Point Function: The quantities that depends on state
only, not on how a system reaches that state are called
Point function. e.g. All thermodynamic properties
• Path Function: A quantity that depends on the state as
well as how the system reaches that state is called path
function. e.g. work, heat

12. • Work :Work is done when the point of application of force moves in the
direction of the force.
W=F.x
• Energy: Energy is defined as the capacity to do work.
Types of Energy:
a) Potential Energy: It is the energy possessed by the body by virtue of
its position above ground level.
𝑃. 𝐸. = 𝑚𝑔𝑍
b)Kinetic Energy: It is the energy possessed by the body
when it is in motion.
𝐾. 𝐸. =
1
2
𝑚𝑣2

13. c) Internal Energy: It is the energy possessed by body due
to its molecular arrangement and motion of molecules.
• Heat: Heat is an energy which is transferred across the
boundary between systems, without transfer of mass, by
reason of the difference in temperature of the two systems
and in the direction of lower temperature.
• Specific Heat: The specific heat of a substance is broadly
defined as the amount of heat required to raise the
temperature of a unit mass of any substance through one
degree.

14. • Enthalpy: The total heat content of the system is called as
enthalpy.
• Entropy: Entropy means transformation. Entropy is a property
of working substance which increases with the addition of heat
and decreases with removal of heat.
𝑑𝑆 = 𝑑𝑄/𝑇

15. LAWS OF THERMODYNAMICS
• Zeroth law: When a body ‘A’ is in thermal equilibrium with
the body ‘B’ and also separately with the body ‘C’ , then
the two bodies ‘B’ and ‘C’ will be in thermal equilibrium
with each other.

16. FIRST LAW OF THERMODYNAMICS
• Law of Conservation of Energy
• The first law says that heat transfer is equal to work
transfer when the system executes a cycle transferring
work & heat through its boundaries.
∮ 𝛿𝑄 = ∮ 𝛿𝑊

17. Limitations of first law of thermodynamics:
• When are closed system undergo a thermodynamic cycle
the net heat transfer is equal to the net work transfer.-This
statement does not specify the direction of flow of heat and
work.
• The heat energy and mechanical work are mutually
convertible.-Work can be fully converted into heat but heat
can not be fully converted into work