# ENGG 311 Lecture 1: Thermodynamics: Complete Notes

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Published on 1 Aug 2016
School
Department
Course
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ENGG is
I
311
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What is Thermodynamics ?
The study of equilibrium processes in which heat is an important variable
Units and Dimensions
.
Dimensions are any quantity to which one can person .be a numerical value
Units are the quantities used to measure dimensions
(1) Primary dimensions are the quantities that can be detected by one of
the senses .In this course we will be concerned with length [L]
mass [M],time ft ]and temperature [8]
In the english system of units ,Force is aprimary dimension .
(2) Derived dimensions are made up of the product or ratio of primary
dimensions
(Ex )velocity .[L][ t]-'
In the 5.1 .system ,force is aderived dimensions
Primary and derived dimensions have primary and derived units .
Dimensions Length Mass Force Energy
SI Units mKg NJ
English Unit ft Ibm the Btu
Externalities
Extensive quantities are those which depends upon the size of the object .for
example mass and volume .
With the exceptions of mass uppercase letters are used for
extensive quantities
Intensive quantities are independent of the size of the system .For example ,density is
is an intensive quantity .With the exception of temperature lower case letters will be Used
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Specific quantities are quantities that are given per unit mass or per unit moles
lower case letters will be used .An under bar implies amolar basis
h[J/kg] or _h[ Ymol ]
System
A system
is any area in space upon which we perform a thermodynamic analysis .Systems
are separated by the surroundings by areal or imagined ,system boundary
.AClosed system is one
in which mass cannot enter or exit the system
An Open system allows both mass and energy to exit or enter
.An Isolated system is one in which no mass or
energy can enter or exit
Properties of asystem :Macroscopic .January lbth
characteristic to which one can assign anumerical value
J
properties
do not depend upon history of the system
For example consider arectangular block of steel .Some of the properties
are length ,width ,height,mass ,temperature and resistivity
The collection of all property values is called the state of the system
Aprocess is achange in the state of asystem
consider an ideal gas Contained in aclosed cylinder
Pn
P,4-R12 fifes
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