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CH-107

Lecture

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CHEMICAL
ENGINEERING
THERMODYNAMICS-I
Dr
...
M Smith, 7th Edition
...

• “Thermodynamics, an Engineering
Approch” by Yunus A Cengel
...


CHEMICAL ENGINEERING THERMODYNAMICS-I

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Faculty of Chemical Engineering, NEDUET

Lecture Outlines
Zeroth law of Thermodynamics
...

Concept of Internal Energy
...

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CHEMICAL ENGINEERING THERMODYNAMICS-I

Faculty of Chemical Engineering, NEDUET

Zeroth law

Zeroth Law of Thermodynamic
 Developed by R
...
Fowler in 1931
...

 It provides the basis for the measurement of temperature of a
system

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CHEMICAL ENGINEERING THERMODYNAMICS-I

Faculty of Chemical Engineering, NEDUET

Zeroth law

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CHEMICAL ENGINEERING THERMODYNAMICS-I

Faculty of Chemical Engineering, NEDUET

Zeroth law

 It is defined as the act of measuring temperature with
accuracy and precision
...


 The sensing element of the device has certain physical
characteristics which change with temperature and this
effect is taken as a measure of temperature

Thermometric Property
 A property or physical characteristic which changes its

value as a function of temperature is called thermometric
property

...


Physical Characteristics
 A change in dimension, like volume expansion
...
g
...

 A change in electrical resistance of the metals and
semiconductors
...
g
...

 A change in the intensity and color of emitted radiations
...

 Suppose ice and steam point of water can be selected as
reference point in one temperature scale
...

 Such as T= Ax+B this is linear relationship
...


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CHEMICAL ENGINEERING THERMODYNAMICS-I

Faculty of Chemical Engineering, NEDUET

Zeroth law

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CHEMICAL ENGINEERING THERMODYNAMICS-I

Faculty of Chemical Engineering, NEDUET

Zeroth law

Thermodynamic Temperature Scale
 A temperature scale that is independent of the properties
of substance is known as the Thermodynamic temperature
scale
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...
8
273
...
15K

Absolute Zero

Triple point of water

-273
...
8
273
...
144 cm3 bar/mole
...
8
273
...
15K
Triple point of water

f (t)= pV=0 0 K

273
...
1ᵡ 10 bar

CHEMICAL ENGINEERING THERMODYNAMICS-I

T (K)
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Faculty of Chemical Engineering, NEDUET

work

Concept Of Work
Work is done when a force „F‟ applied on a object and it
moves the object to a certain distance „l‟

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CHEMICAL ENGINEERING THERMODYNAMICS-I

Faculty of Chemical Engineering, NEDUET

work

Concept Of Work
Expansion / Compression Work

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CHEMICAL ENGINEERING THERMODYNAMICS-I

Faculty of Chemical Engineering, NEDUET

work

Concept Of Work
Sign Convention for Work
 Work done on the system
...


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CHEMICAL ENGINEERING THERMODYNAMICS-I

Faculty of Chemical Engineering, NEDUET

work

Path Dependency of Work

Final State,S2

P2

*
*Initial State,S1

P1

V2

V1
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CHEMICAL ENGINEERING THERMODYNAMICS-I

Faculty of Chemical Engineering, NEDUET

work

Path Dependency of Work

Final State,S2
P2

Final State,S2

*

P2

*Initial

P1

*
*Initial State,S1

P1

State,S1
V2

V1

V2

V1

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CHEMICAL ENGINEERING THERMODYNAMICS-I

Faculty of Chemical Engineering, NEDUET

work

Path Dependency of Work

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CHEMICAL ENGINEERING THERMODYNAMICS-I

Faculty of Chemical Engineering, NEDUET

work

Path Dependency of Work

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CHEMICAL ENGINEERING THERMODYNAMICS-I

Faculty of Chemical Engineering, NEDUET

work

Work On Cyclic Path

Cooling
Heating

Wtotal = W1 – W2

Final State,S2

P2

*
*Initial State,S1

P1

V2

V1
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CHEMICAL ENGINEERING THERMODYNAMICS-I

Faculty of Chemical Engineering, NEDUET

work

Path Dependency of Work
Final State,S2

P1

Heating

P2

(Process Path 1)

*
Cooling

*Initial State,S1

*

Heating

P2

Cooling

V1
(Process Path 2)
Final State,S2
Cooling

Heating

V2

*Initial State,S1

P1

V2

V1
CHEMICAL ENGINEERING THERMODYNAMICS-I

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Faculty of Chemical Engineering, NEDUET

work

Work On Cyclic Path
Final State,S2
Heating

P1

*

Cooling

P2

Heating

Cooling

*Initial State,S1
Wtotal = W1 – W2

V2

V1

Cooling
Heating
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CHEMICAL ENGINEERING THERMODYNAMICS-I

Faculty of Chemical Engineering, NEDUET

Heat

HEAT (Q)
Heat is a Caloric Fluid (Magical Fluid)
...

Heat is form of energy which transfer across the
boundary of a system and surrounding because of
the temperature difference
...

If heat inters in to the system it is positive / If going
out of the system it is negative
...

 Adiabatic Temperature Change
...

 Heat is a Path Function, not a state function
...


Path
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CHEMICAL ENGINEERING THERMODYNAMICS-I

Faculty of Chemical Engineering, NEDUET

Heat

Heat Capacity
 It relates the amount of heat added to the system with temperature
...

 Specific heat separates the different materials
...

Const P

Fixed Volume
P,T

V

P

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CHEMICAL ENGINEERING THERMODYNAMICS-I

Faculty of Chemical Engineering, NEDUET

Heat

Specific Heat Capacity
 On the basis of specific heat value different materials selected
for different applications
...


 Low Specific Heat materials
...


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CHEMICAL ENGINEERING THERMODYNAMICS-I

Faculty of Chemical Engineering, NEDUET

Heat

Relation Btw Heat & Temperature
V

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CHEMICAL ENGINEERING THERMODYNAMICS-I

Faculty of Chemical Engineering, NEDUET

Heat

Relation Btw Heat & Temperature

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CHEMICAL ENGINEERING THERMODYNAMICS-I

Faculty of Chemical Engineering, NEDUET

Heat

Problem Specific Heat Capacity

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CHEMICAL ENGINEERING THERMODYNAMICS-I

Faculty of Chemical Engineering, NEDUET

Heat

Problem Specific Heat Capacity

What do you think!
The values of Cp and Cv for liquid ,solid and gas phase of the materials
are same or not?

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CHEMICAL ENGINEERING THERMODYNAMICS-I



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