AMALIA SHOLEHAH JURUSAN TEKNIK METALURGI FT – UNTIRTA THERMODYNAMICS.
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Transcript of AMALIA SHOLEHAH JURUSAN TEKNIK METALURGI FT – UNTIRTA THERMODYNAMICS.
AMALIA SHOLEHAHJURUSAN TEKNIK METALURGI
FT – UNTIRTA
THERMODYNAMICS
Overview
General Chemistry Physical Chemistry
First Law:The internal energy of an isolated system is constant
Zeroth Law:If two thermodynamics systems are in thermal equilibrium with a third, they are also in thermal equilibrium with each other
First Law:The energy of an isolated system is constant. It implies that energy can never be created or destroyed, it can only change its form. For a system U = q + w ; Where (U) represents a change in internal energy, (q) is the change in thermal energy and (w) is the work done
Second Law:A spontaneous change is accompanied by an increase in the total entropy of the system and its surroundings
Second Law:Whenever a spontaneous event takes place it is accompanied by an increase in the entropy of the universe
Third Law:For a pure crystalline substance, S = 0 at 0°K
Study of the patterns of energy change" thermo" energy
"dynamics" the patterns of changeDeals mainly with
(A) energy conversion (B) the stability of molecules (C) direction of change
Laws of Thermodynamics
They control interactions of everything in the universe - regardless of scale
Classical physics is, from a certain perspective, entirely based on Newton's Laws of motion only applicable in certain conditions
Development of the Laws of Thermodynamics actually began thousands of years ago
The largest advancements in developing the Laws of Thermodynamics occurred in the mid-1800s Joule’s experiment First Law of Thermodynamics
Not long after Clausius theory Second Law of Thermodynamics
Around 1906 Nernst theory Third Law of Thermodynamics
State of a System
System physical universe that is under consideration
System is separated from rest of universe by Real / Imaginary boundary
Surroundings part of universe outside the boundary
Thermodynamics Properties
Extensive properties Depend on the size of the system Ex : Volume (V), mass
Intensive properties Not depend on the size of the ystem Ex : Pressure (P), Temperature (T), density
Thermodynamics Process
P – V conjugate pair transfer of mechanical or dynamic energy as the result of work Isobaric process occurs on constant pressure
(dynamically connected) Isochoric / isometric process occurs on constant
volume (dynamically insulated)
T – S conjugate pair transfer of thermal energy as the result of heating Isothermal process occurs on constant temperature
(thermally connected) Isentropic process occurs on constant entropy Adiabatic process no energy added or subtracted
from the system by heating or cooling (thermally insulated)
State Variables (Thermodynamic Coordinates)
When a system is at equilibrium its state defined entirely by the state variable not depend on history of system
Ex : pressure (P), temperature (T), internal energy (U), enthalpy (H), enthropy (S), and Gibbs energy (G)
Zeroth Law
“ If two thermodynamics systems are in thermal equilibrium with a third, they are also in
thermal equilibrium with each other ”
A B
C
A system in thermal equilibrium is a system whose macroscopic properties (like pressure, temperature, volume, etc.) are not changing in time
When two systems are in thermal equilibrium: both of the systems are in a state of equilibrium, they remain so when they are brought into
contact, where 'contact' is meant to imply the possibility of exchanging heat, but not work or particles
If a fluid is in thermal equilibrium with another system: it has only one independent variable the macroscopic properties have certain values
Isotherm Plot
Boyle’s Law PV = f(θ)
Gay-Lussac’s Law (PV)1
(PV)2
= (1, 2)
(PV)1
(PV)2
=T1
T2
= (PV)2
T2
(PV)1
T1
Ideal gas
R = ideal gas constant
(PV)T
= nR