1-Basic concept of thermodynamics
2-Properties of pure substances
3-Ideal gas laws
4 - Energy, energy transfer and analysis
5-First law of thermodynamics
6-Second law of thermodynamics
Two kind of properties:
Any physical quantities can be charactherized by Dimensions
Ideal Gas Law
(Low Pressure and High Temperature) + Low Density
Problems of Ideal Gas
PV = nR(u)T
P = Absolute Pressure (Pab = Patm + Pgauge)
V = Volume or specific volume depending on equation
Pressure; P= F/A, force per unit area
Units are the magnitudes assigned to the dimensions.
T = Absolute Temperature (0 Kelvin)
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Three types of system
Second Law of Thermodynamics
closed system
isolated system
open system
Equation of states: any equation that relates properties of a system at equilibrium.
Thermodynamics Process and Cycle
R(u) = universal gas constant
both mass and energy can cross the boundary
no mass can enter or leave the system except energy
Kelvin-Planck's Statement
(Heat Engine)
PV = mRT
Clausius's Statement
(Refrigerator + Heat Pump)
System=quantity of matter/region in space chosen for study
no mass and energy can enter or leave the system
2) Mechanical Equilibrium
1)Thermal Equilibrium
Thermodynamics process is the specific way in which internal
energy is exchanged
4)Chemical Equilibrium
Ideal gas are gas whose molecules occupies negligible space and does not contribute to the interactions of the gas. Thus, it obeys the ideal gas law.
conservation of energy
ΔU=Q-W
adiabatic ( no heat added or release; Q = 0 J)
isobaric ( constant pressure , P=0 )
Surrounding= mass/region outside system
First law of thermodynamics
isochoric ( constant volume, V=0 )
boundary= real/imaginary surface that separates system from its surrounding
isothermal ( constant temperature , T=0)
pressure cooker
Pure Substances
Path of the process :
Critical Point =the saturated liquid and saturated vapour states are identical ( no saturated mixture exists)
ΔU = change in internal energy
Intensive properties: Independent of the size of the system.
Eg: T,P, density, any mass independent property.
Q = heat added to the system
a series of states through which a system passes
during a process
3)Phase Equilibrium
Extensive properties : depend on the mass of system, Ex: total mass, total volume, total momentum
W = work done by the system
thermo flask
R = Ru/M. M is molar mass of gas
Temperature is the same throughout the system
Quasi-static process:
boiling water without lid
n = m/M where m is mass of gas and M is the molar mass of gas
Secondary or Derived Dimensions
when a process proceeds in a manner where the system is close to equilibrium (slow process)
energy can be neither created nor destroyed
Primary or Fundamental Dimensions
No change in pressure at any point of the system with time
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Compressibility Factor, Z
The mass of each phase reaches an equilibrium level and stays there
Energy balance
Chemical composition does not change with time
ΔE = E2-E1
phase= a pure substance may exist in more than one phase
Types of Thermodynamic Processes
Basic concept of thermodynamics
Reversible: Can happen slowly in either direction.
mass m, length L, time t, and temperature T
Z < 1 or Z >1 (Deviation of real gas from ideal gas)
velocity V, energy E, and
volume V
Irreversible: Involves net increase in entropy (can’t go
backwards).
Zeroth Law of thermodynamics: The zeroth law states that if two systems are at the same time in thermal equilibrium with a third system, they are are in thermal equilibrium with each other.
Z = 1 (Gas obeys Ideal Gas Law)
Use Compressibility Chart
Z = V(actual)/V(ideal)
It is impossible for ay devices that operates on a cycle to receive heat from a single reservoir and produce net work
Can be used to calculate errors
It is impossible to construct a device which operates a cycle and produce no effect other than the transfer of heat from a lower-temperature body to a higher-temperature body.
P(reduced) = P/P(critical)
T(reduced) = T/T(critical)
We can use Pr and Tr for compressibility factor chart
Cycle is a sequence of different processes that begins and ends
at the same thermodynamic state
work done
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W= nRT ln(P1/P2)
W=nRT ln(V2/V1) - isothermal procession
Van der Waals Equation
For sample of ideal gas
Used to describe intermolecular forces and volume occupied by the molecules
Enthalpy formula : H = E + PV
Isobaric: Constant Pressure
Isochoric: Constant Volume
Adiabatic: No heat added or release
Isothermal: Constant Temperature
Work done,W = Q1-Q2
Thermal Efficiency, n = (Q1-Q2)/Q1
Polytropic process
P = CV*(-n)
P = TV* (1-n)
Isochoric process W=0
isobaric process W=P(V2-V1)
Adiabatic Process for Ideal gas W=nCv(T1-T2)
definition of enthalpy:
a thermodynamic quantity equivalent to the total heat content of a system
Property Tebles
Compressed Liquid
Saturated Liquid/Vapour
Superheated Vapour
P - h diagram