# Thermodynamics - Kvagra1.org.in

Mechanics

Oct 27, 2013 (4 years and 6 months ago)

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Teacher Orientation

Name Of Teacher

:
-

T Siddiqui

KV AFS MEMORA LUCKNOW

Subject
:
-

Chemistry

Topic

:
-

Thermodynamics

C
lass
: XI

Details:
-

(i)

System & surrounding

Thermodynamics is conducted under a
system
-
centered view

of the universe. All quantities, such
as
pressure

or
mechanical work
, in an equation refer to the system unless labeled otherwise.
Thermodynamics is basically concerned with the flow and balance of energy and matter in a
thermodynamic system. Three types of thermo
dynamic systems are distinguished depending on
the kinds of interaction and
energy

exchange taking place between the system and its
surrounding environment:

Isolated systems

are completely isolated in every way from their environment. They do not
exchange heat, work or matter with their environment. An example of an isolated system would
be an insulated rigid cont
ainer, such as an insulated gas cylinder.

Closed systems

are able to exchange energy (heat and work) but not matter with their
environment. A greenhouse is an example of a close
d system exchanging heat but not work with
its environment. Whether a system exchanges heat, work or both is usually thought of as a
property of its boundary.

Open systems
: exchanging energy (heat and work) and matter with their environment. A
boundary allowing matter exchange is called
permeable
. The ocean would be an example of an
open system.

In reality, a system can never be absolutely isolated
from its environment, because there is
always at least some slight coupling, even if only via minimal gravitational attraction. In
-
state, the energy into the system is equal to the energy leaving the
system
[1]
.

As an example, consider the system of hot liquid
water

and solid
table salt

in a sealed, insulated
test tube held in a vacuum (the surroundings). The test tube constantly loses heat (in the form of
black
-
n
), but the heat loss progresses very slowly. If there is another process going
on in the test tube, for example the
dissolution

of the salt
crystals
, it will probably occur so
quickly that any heat lost to the test tube during that time can be neglected.

(ii)

Extensive & Intensive Properties

(iii)

State Function

(iv)

Heat Work &Internal Energy

(v)

First law of T.D.

Laws of thermodynamics

The present article is focused on classical thermodynamics, which is focused on systems in
thermodynamic equilibrium
. It is wise to distinguish classical thermodynamics from
non
-
equilibrium thermodynami
cs
, which is concerned with systems that are not in
thermodynamic
equilibrium
.

In thermodynamics, there are four laws that do not depend on the details o
f the systems under
study or how they interact. Hence these laws are very generally valid, can be applied to systems
about which one knows nothing other than the balance of energy and matter transfer. Examples
of such systems include
Einstein
's prediction, around the turn of the 20th century, of
spontaneous
emission
, and ongoing research into the the
rmodynamics of
black holes
.

These four laws are:

Zeroth law of thermodynamics
thermal equilibrium
:

If two
thermodynamic systems

are separately

in thermal equilibrium with a third, they are also
in thermal equilibrium with each other.

If we grant that all systems are (trivially) in thermal equilibrium with themselves, the Zeroth law
implies that thermal equilibrium is an
equivalence relation

on the set of
thermodynamic
systems
. This law is tacitly assumed in every m
easurement of temperature. Thus, if we want to
know if two bodies are at the same
temperature
, it is not necessary to bring them into contact
and to watch whether their observable pr
operties change with time.
[15]

This law was considered so obvious
[
citation needed
]

it was added as a virtual afterthought, hence the
designation Zeroth, rather than Fourth. In short, if the heat energy of material A is equal to the
heat energy of material B, and B is equal to the heat energy of material C. then A and

C must
also be equal.

First law of thermodynamics
conservation of energy
:

The change in the
internal energy

of a closed
ther
modynamic system

is equal to the sum of the
amount of
heat

energy supplied to or removed from the system and the
work

done on or by the
system. So, we can say (1) "Energy is neither created nor destroyed" and (2) "There is no free
lunch."
[16]

Second law of thermodynamics
entropy
:

The total entropy of any isolated thermodynamic system always in
creases over time,
approaching a maximum value or we can say, "In an isolated system, the entropy never
decreases". Another way to phrase this: Heat cannot
spontaneously

flow from a colder location
to a hotter area
-

work is required to achieve this.

Third law of thermodynamics
absolute zero

of
temperature
:

(vi)

(vii)

Enthalpy Of Reaction

(viii)

Enthalpy Of Formation,Combustion,Fusion,etc

(ix)

Hesse’s Law

(x)

Entropy

Entropy

is a measure of how disorganized a syste
m is:
"Gain of entropy eventually is nothing
more nor less than loss of information

(xi)

Spontaneity

A
spontaneous process

is the time
-
evolution of a system in which it releases
free energy

(most
often as heat) and moves to a lower, more thermodynamically stable, energy state.
[1]
[2]

The sign
convention of changes in free energy follows the general convention for
thermodynamic

measurements, in which a release of free

energy from the system corresponds to a negative
change in free energy, but a positive change for the surroundings.

A spontaneous process is capable of proceeding in a given direction, as written or described,
without needing to be driven by an outside so
urce of energy. The term is used to refer to
macro processes in which
entropy

increases; such as a smell diffusing in a room, ice melting in
lukewarm water, salt dissolving in water, and iro
n rusting

(xii)

2
nd

Law of T.D.

(xiii)

Gibb’s energy & equation

TEACHER’S DESK

EVALUATION TOOLS

Subject

:
-

Chemistry

Topic :
-

Thermodynamics

Class:

XI

CONCEPT
:

Concept Details:
-
First law of TD

Tota
l Energy of the universe is constant

Home Work

Answer the Questions Given in NCERT text Book Exercise

Assignment

Define following terms:

(i)Work

(ii)Inter
nal Energy

(iii)1
st

Law of TD

(v) Entropy

Project

Study the entropy change in surrounding of you (at least five)

References
:

(i)NCERT text Book

(ii)