PHYSICAL CHEMISTRY THERMODYNAMICSII THERMODYNAMICS II LIMITATION OF FIRST LAW OF THERMODYNAMICS It does not give information concerning feasibility of a thermodynamic process why NOT EXPLAINED BY FIRST LAW ID: 166918
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Slide1
BSC. -II
PHYSICAL CHEMISTRY
THERMODYNAMICS-IISlide2
THERMODYNAMICS -IISlide3
LIMITATION OF FIRST LAW OF
THERMODYNAMICS
It does not give information concerning feasibility of a thermodynamic
process.
why
NOT EXPLAINED BY FIRST LAWSlide4
It tells that work obtained is equal to heat absorbed but in actual heat absorbed can not be completely converted into work
.
Limitations motivating second lawSlide5
5
The
second law of thermodynamics
It will arouse changes while the heat transfers from low temp.substance to high temp. one.Slide6
DIFFERENT STATEMENTS OF
SECOND LAW
All spontaneous processes are thermodynamically irreversible.
. Slide7
The complete conversion of heat into work is impossible without leaving its effects somewhere.
SOME AMOUNT OF HEAT MOVES TO SURROUNDINGSlide8
Without the use of any external agency ,heat can not by itself pass from a colder body to a hotter body
HOT
BODY
COLD BODY
HEAT TRANSFER
EXTERNAL AGENCYSlide9
Carnot cycle and its efficiency
Sadi
Carnot devised a technique, called Carnot Cycle.
Carnot chose a reversible heat engine ,.known as
carnot engine, consisting of one mole of ideal gas , fitted with frictionless piston ,insulated on all sides except bottom. This engine is having 2 heat reservoirs , one at higher temperature T2 and the other at a lower temperature T
1.The Carnot Cycle consists of 4 different operations:Isothermal expansion
Adiabetic expansionIsothermal compressionAdiabetic compressionSlide10Slide11
ISOTHERMAL(T
2
)
ISOTHERMAL(T
1
)
ADIABETIC
ADIABETIC
I
II
III
IV
PRESSURE
VOLUMESlide12
Carn carnot cycle
State 1
T2
State 2
T2
State 4
T1
State 3T1
isothermal
adiabatic
adiabatic
isothermal
q=0,
W
4
=
C
v
T
q=0,
w
2
=-
C
V
T
w
1
= -RT
2
ln(V2/V1
)
q
2
=-
w
w
3
= RT
1
ln(V4/V3
)
-q
1
=w
3Slide13Slide14Slide15Slide16Slide17Slide18Slide19Slide20Slide21Slide22Slide23Slide24Slide25Slide26Slide27Slide28Slide29Slide30Slide31Slide32Slide33Slide34Slide35Slide36Slide37Slide38Slide39Slide40Slide41Slide42Slide43Slide44Slide45Slide46Slide47Slide48Slide49Slide50Slide51Slide52Slide53Slide54Slide55Slide56Slide57Slide58Slide59Slide60Slide61Slide62Slide63Slide64Slide65Slide66Slide67Slide68Slide69Slide70Slide71Slide72Slide73Slide74Slide75Slide76Slide77Slide78Slide79Slide80Slide81Slide82Slide83Slide84Slide85Slide86Slide87
Carnot Cycle
State 1Thot
State 2T
hot
State 4Tcold
State 3Tcold
isothermal
adiabatic
adiabatic
isothermal
q=0,
w=C
V
T
q=0,
w=-C
V
T
w= -nRT
hot
ln(V2/V1)
q=-w
w= -nRT
cold
ln(V4/V3)
q=-wSlide88Slide89Slide90Slide91Slide92Slide93Slide94Slide95Slide96Slide97Slide98Slide99Slide100Slide101Slide102Slide103Slide104Slide105Slide106Slide107Slide108Slide109Slide110Slide111Slide112Slide113Slide114
114
The second law of thermodynamics
It will arouse changes while the heat transfers from low temp.substance to high temp. one.Slide115Slide116Slide117Slide118Slide119Slide120Slide121
121
The second law of thermodynamics
It will arouse changes while the heat transfers from low temp.substance to high temp. one.Slide122Slide123Slide124Slide125Slide126Slide127Slide128Slide129Slide130Slide131Slide132Slide133Slide134Slide135Slide136Slide137Slide138Slide139Slide140Slide141Slide142Slide143Slide144Slide145Slide146Slide147Slide148Slide149Slide150