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CBSE Class 11 Chemistry Thermodynamics – Get here the Notes for Class 11 Thermodynamics. Candidates who are ambitious to qualify the Class 11 with good score can check this article for Notes. This is possible only when you have the best CBSE Class 11 Chemistry study material and a smart preparation plan. To assist you with that, we are here with notes. Hope these notes will helps you understand the important topics and remember the key points for exam point of view. Below we provided the Notes of CBSE Class 11 Chemistry for topic Thermodynamics.

What is Thermodynamics?
Thermodynamics in physics is a branch that deals with heat, work and temperature, and their relation to energy, radiation and physical properties of matter.

 Thermal Equilibrium:- Two systems are said to be in thermal equilibrium
with each other if they have the same temperature.

 Thermo dynamical system:- An assembly of large numbers of particles
having same temperature, pressure etc is called thermo dynamical system.

 Thermodynamic variables :- The variables which determine the
thermodynamic behavior of a system are called thermodynamic variables

 Zeroth law of Thermodynamics :- IT states that if two system A and B are in
thermal equilibrium with a third system C , then the two system A and B are
also in thermal equilibrium with each other.

 Thermodynamic Process :- A thermodynamic process is said to be taking
place , if the thermodynamic variable of the system change with time.

 Types of thermodynamic Process:-
(1) Isothermal process – process taking place at constant temperature.
(2) Adiabatic process – process where there is no exchange of heat.
(3) Isochoric process – process taking place at constant volume
(4) Isobaric process –Process taking place at constant Pressure.
(5) Cyclic process:- Process where the system returns to its original state.

 Equation of state : A relation between pressure, volume and temperature
for a system is called its equation of state .

 Indicator diagram (P-V diagram) :- The graphical representation of the
state of a system with the help of two thermodynamical variables is called
indicator diagram of the system.

 Internal energy of a gas :- It is the sum of kinetic energy and the
intermolecular potential energy of the molecules of the gas. Internal energy is
a function of temperature.

 First law of Thermodynamics :- It states that if an amount of heat dQ I
added to a system , a part of heat is used in increasing its internal energy
while the remaining part of heat may be used up as the external work done
dW by the system.

Mathematically :-

dQ=dU+dW
dQ=dU+ PdV.

 Work done during expansion / compression of gas:- when the volume of gas changes from V1 to V2 , the work done is given by W= ∮ = Area under the p -V diagram.

 Thermodynamical operations are
(1) Isothermal process : A thermodynamic process that takes place at constant temperature is called an isothermal process.
– Equation of state for isothermal process : PV = constant.
– Work done during an isothermal process
Wiso = RT loge
= 2.303 RT loge


(2) Adiabatic process : A thermodynamic process that takes place in such a
manner that no heat enters or leaves the system is called adiabatic process

 Equation of state for adiabatic process :- It is a process in which the system can be retraced to
its original state by reversing the condiditions.

 Irreversible process:- It is a process in which the system cannot be retraced
to its original state by reversing the conditions.

 Second law of thermodynamics:

 Kelvin’s statement of second law – It is impossible to derive a
continous supply of work by cooling a body to a temperature lower than
that of the coldest of its surrounding.

 Clausius statement of second law – It is impossible for a self –acting
machine unaided by any external agency to transfer heat from a body to
another body at higher temperature.

 Heat Engine – a heat engine is a device for converting heat energy
continuously into a mechanical work.

 Component of heat engine-

(i) source of heat

(ii) Sink

(iii) Working substance

 Efficiency of heat Engine :-It is defined as the ratio of the external work
obtained to the amount of heat energy absorbed from the heat source.

 Carnot’s heat Engine :- it is an ideal heat Engine which is based on carnot’s
reversible cycle.
Efficiency of carnot’s heat Enginen

 Refrigerator or Heat pump:- it is heat engine working backward.

 Co-efficient of performance : It is the ratio of heat absorbed from cold body
to the work done by the refrigerator.