this is a ppt just for the teachers wanting to give an intro to thermodynamics hope you like it ! - made by ritik tatia !

1. ThermodynamicsThermodynamics

2. What is thermodynamicsWhat is thermodynamics??
 Thermodynamics is that branch of science thatThermodynamics is that branch of science that
deals with the quantitative relationshipdeals with the quantitative relationship
between heat and other forms of energy.between heat and other forms of energy.
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3. Some basic terms of thermodynamicsSome basic terms of thermodynamics
 System :- a specified part ofSystem :- a specified part of
the universe that is underthe universe that is under
observation.observation.
 Surroundings:- the part otherSurroundings:- the part other
than the system is known as thethan the system is known as the
surroundings.surroundings.
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4. Types of systemsTypes of systems
 Open system :- the system thatOpen system :- the system that
can exchange matter as well ascan exchange matter as well as
energy with the surroundings.energy with the surroundings.
 Closed system:- the systemClosed system:- the system
which cannot exchange matterwhich cannot exchange matter
but can exchange energy with thebut can exchange energy with the
surroundings.surroundings.
 Isolated system:- the systemIsolated system:- the system
which cannot exchange matter aswhich cannot exchange matter as
well as energy is called anwell as energy is called an
isolated system.isolated system.
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5. Macroscopic and microscopic propertiesMacroscopic and microscopic properties
 Macroscopic propertiesMacroscopic properties are thoseare those
properties which arise from theproperties which arise from the
bulk behaviour of matter. Eg:-bulk behaviour of matter. Eg:-
temperature , viscosity.temperature , viscosity.
 Microscopic propertiesMicroscopic properties are thoseare those
properties which arise from theproperties which arise from the
microscopic particles of themicroscopic particles of the
system .Eg:- intermolecularsystem .Eg:- intermolecular
forces.forces.
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6. Intensive and extensive propertiesIntensive and extensive properties
 Intensive properties are thoseIntensive properties are those
properties whose value isproperties whose value is
independent upon theindependent upon the
amount of substance presentamount of substance present
in the system . Eg:-in the system . Eg:-
temperature.temperature.
 Extensive properties areExtensive properties are
those properties whose valuethose properties whose value
does depends upon thedoes depends upon the
amount of substance presentamount of substance present
in the system.in the system. 6
Intensive properties

7. State of the systemState of the system
 The condition of existence of a system whenThe condition of existence of a system when
the macroscopic properties have definite valuethe macroscopic properties have definite value
is called the state of the system.is called the state of the system.
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8. State FunctionsState Functions
A state functionA state function depends only on the present state of the systemdepends only on the present state of the system,,
not on the pathnot on the path by which the system arrived at that state.by which the system arrived at that state.
•Other state functions are P, V and T.
•However, q and w are not state functions.

9. State variables or state functionsState variables or state functions
 A thermodynamic propertyA thermodynamic property
whose value depends on thewhose value depends on the
initial and final states of theinitial and final states of the
system and is independent ofsystem and is independent of
the manner by which thethe manner by which the
change is bought about.change is bought about.
 The process which bringsThe process which brings
changes in the system is calledchanges in the system is called
a thermodynamic process.a thermodynamic process.
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10. Internal energyInternal energy
 The chemical nature of theThe chemical nature of the
substance depends about the energysubstance depends about the energy
which it possesses and alsowhich it possesses and also
depends upon the state of itsdepends upon the state of its
existence which is known as theexistence which is known as the
internal energy.internal energy.
 It also depends upon the kineticIt also depends upon the kinetic
energy of the particles in theenergy of the particles in the
system.system.
 It is an extensive property.It is an extensive property.
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11. EnthalpyEnthalpy
 The sum of the internalThe sum of the internal
energy and the sum of theenergy and the sum of the
pressure volume work ispressure volume work is
known as the enthalpy of theknown as the enthalpy of the
system.system.
 Enthalpy is also an extensiveEnthalpy is also an extensive
property.property.
 Enthalpy is denoted by “H”.Enthalpy is denoted by “H”.
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12. Reversible and irreversible processReversible and irreversible process
 A reversible process is a process when itA reversible process is a process when it
is carried out slowly so that the systemis carried out slowly so that the system
and the surroundings are always atand the surroundings are always at
equilibrium then the process is termed asequilibrium then the process is termed as
a reversible process.a reversible process.
 An irreversible process is a process whichAn irreversible process is a process which
takes place rapidly in the system such thattakes place rapidly in the system such that
the system and the surroundings are not atthe system and the surroundings are not at
equilibrium.equilibrium.
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13. The Zeroth Law of Thermodynamics
If object A is in thermal
equilibrium with object C,
and object B is separately
in thermal equilibrium with
object C, then objects A
and B will be in thermal
equilibrium if they are
placed in thermal contact.

14. The First Law of Thermodynamics
The first law of thermodynamics is a statement of the conservation of
energy.
If a system’s volume is constant, and heat is added, its internal energy
increases.

15. The First Law of Thermodynamics
If a system does work on the external world, and
no heat is added, its internal energy decreases.

16. The First Law of Thermodynamics
Combining these gives the first law of thermodynamics. The change
in a system’s internal energy is related to the heat Q and the work W
as follows:

17. The First Law of Thermodynamics
The internal energy of the system depends only on its temperature.
The work done and the heat added, however, depend on the details of
the process involved.

18. Thermal Processes
This is an idealized reversible process. The gas is
compressed; the temperature is constant, so heat leaves
the gas. As the gas expands, it draws heat from the
reservoir, returning the gas and the reservoir to their
initial states. The piston is assumed frictionless.

19. Thermal Processes
Work done by an expanding gas, constant pressure:

20. Thermal Processes
If the volume stays constant, nothing moves and
no work is done.

21. Thermal Processes
If the temperature is constant, the
pressure varies inversely with the
volume.

22. Thermal Processes
The work done is the area under the curve:
--

23. Thermal Processes
An adiabatic process is one in which no heat flows
into or out of the system. The adiabatic P-V curve is
similar to the isothermal one, but is steeper. One way
to ensure that a process is adiabatic is to insulate the
system.

24. Another way to ensure
that a process is
effectively adiabatic is
to have the volume
change occur very
quickly. In this case,
heat has no time to
flow in or out of the
system.
Thermal Processes

25. Energy as Work (Energy as Work (ww) of Gas Expansion) of Gas Expansion
Work Gas Expansion
Work = - (Force
x distance(
w = - (F x ∆h(
w = - (P x A x ∆h(
w = - P ∆V
)at constant P(
w = - ∆nRT
)at constant V(
There fore

26. Exchange of Heat (Exchange of Heat (∆∆H)H)
by chemical systemsby chemical systems
•When heat is released by the
system to the surroundings, the
process is exothermic.
•When heat is absorbed by
the system from the
surroundings, the process is
endothermic.
-∆H
+
∆H
q
q

27. Enthalpies of Reaction (Enthalpies of Reaction (∆∆HH((
TheThe changechange in enthalpy,in enthalpy, ∆∆HH,,
is the enthalpy of theis the enthalpy of the
products minus the enthalpyproducts minus the enthalpy
of the reactants:of the reactants:
∆∆HH == HHproductsproducts −− HHreactantsreactants
This quantity, ∆H, is called the enthalpy of
reaction, or the heat of reaction.
Reactants:
Products