Introduction History Definition Law of thermodynamics 1st Law of thermodynamics 2nd Law of Thermodynamics 3rd Law of thermodynamics Application Conclusion Reference

1. By
KAUSHAL KUMAR SAHU
Assistant Professor (Ad Hoc)
Department of Biotechnology
Govt. Digvijay Autonomous P. G. College
Raj-Nandgaon ( C. G. )

2.  Introduction
 History
 Definition
 Law of thermodynamics
A. 1st Law of thermodynamics
B. 2nd Law of Thermodynamics
C. 3rd Law of thermodynamics
 Application
 Conclusion
 Reference
Content

3. Introduction
• The four laws of thermodynamics define fundamental physical quantities
(temperature, energy, and entropy) that characterize thermodynamic systems.
• Thermodynamics is the study of the energy, principally heat energy that
accompanies chemical or physical changes.
• Some chemical reactions release heat energy; they are called exothermic
reactions, and they have a negative enthalpy change.
• Others absorb heat energy and are called endothermic reactions, and they have a
positive enthalpy change. But thermodynamics is concerned with more than just
heat energy.
• The change in level of organization or disorganization of reactants and products as
changes take place is described by the entropy change of the process. For
example, the conversion of one gram of liquid water to gaseous water is in the
direction of increasing disorder, the molecules being much more disorganized as a
gas than as a liquid.
• The increase in disorder is described as an increase in entropy, and the change in
entropy is positive.
• Whether a chemical reaction or physical change will occur depends

4. Definition
• ‘the branch of physical science that deals with the
relations between heat and other forms of energy (such
as mechanical, electrical, or chemical energy), and, by
extension, of the relationships between all forms of
energy.’

5. History
• Around 1850 Rudolf Clausius and William
Thomson (Kelvin) stated both the First Law -
that total energy is conserved - and the
Second Law of Thermodynamics.

6. Thermodynamic system
1. Open system
2. Closed system
3. Isolated system

7. Thermodynamic law
First Law of Thermodynamics
Heat and work are forms of energy transfer. Energy is invariably conserved
but the internal energy of a closed system changes as heat and work are
transferred in or out of it.
This states that energy can be neither created nor destroyed. However,
energy can change forms, and energy can flow from one place to another. The
total energy of an isolated system remains the same.
E = MC2

8. Second Law of Thermodynamics
•The Second Law of Thermodynamics states that heat can never flow from a cold body to a
warmer one. An equivalent definition is that the entropy of an isolated system cannot
decrease.
•Because there are no perfectly closed systems, the Second Law of Thermodynamics holds
that everything becomes more disordered over time, in the absence of intelligent intervention.
•According to this law, it is impossible to build a perpetual motion machine because
increasingly entropy will inevitably derail the machine.
∆suniv = ∆s system +∆s sum
∆s=q/(T)
∆U= 0
qrev = - w
∆U = (q + w)

9. Third Law of thermodynamics
Gibbs energy (also referred to as ∆G) is also the chemical potential that is minimized
when a system reaches equilibrium at constant pressure and temperature.
 Its derivative with respect to the reaction coordinate of the system vanishes at the
equilibrium point.
The Gibbs free energy, originally called available energy, was developed in the 1870s by
the American mathematician Josiah Willard Gibbs. In 1873, Gibbs described this "available
energy" as.
Exam = ∆G = ∆G(product) − ∆G (Reach)
∆G = ∆H −T∆S
∆G = Free energy
∆H = change in enthalpy
T = constant temperature
∆S= change in entropy

10. Application
Experiments on dilute gases show that only pressure, P, the temperature, T, the
number of moles of the gas, n, and the gas volume, V needed to describe system.
In physics we are commonly interested in themovement of energy. This is useful because energy is
neither created or destroyed.
•.
Thermodynamic equilibrium: condition in which equilibrium exists with respect to P,
T, and concentration

11. Conclusion
 The first conclusion is that the universe had to have
a beginning. “If the entire universe is an isolated
system, then, according to the Second Law of
Thermodynamics, the energy is the universe that is
available for useful work has always been decreasing.

12. Reference
 Biotechnology book by – K.C. soni
 chemistry book
 www google.com