[محمد عمر]

Dear universty students
in this page we will talk together about (THERMODYNAMICS) ; beacause it may help you in your colleague . i will make it in sections
with pleasure for every arabian student to be better
mohamed omar- pharmacy collegue
to be continued...............

[محمد عمر]

section 1 : introduction
Thermodynamics (Greek: thermos = heat and dynamis = power) is the physics of heat, work, enthalpy, and entropy changes in relation to the spontaneity of processes. In origins, thermodynamics is the study of engines. Prior to 1698, with the invention of the Savery Engine, horses were used to "power" pulleys, attached to buckets, which lifted water out of flooded salt mines in England. In the years to follow, more variations of steam engines were built; as the Newcomen Engine, and later the Watt Engine. In time, these early engines would eventually be utilized in place of horses. Thus, each engine began to be associated with a certain amount of "horse power" depending upon how many horses it had replaced! The main problem with these first engines was that they were slow and clumsy, converting less than 2% of the input fuel into useful work. In other words, large quantities of coal (or wood) had to be burned to yield only a small fraction of work output. Hence the need for a new science of engine dynamics was born.

Thermodynamics, at present, designates the science of all transformations of matter and energy. Definitively, thermodynamics can be divided into two main branches:

Equilibrium Thermodynamics: the study of systems as they approach equilibrium.
Classical Thermodynamics – macroscopic analysis of systems
Statistical Thermodynamics – microscopic analysis of systems
Non-equilibrium Thermodynamics: the study of systems away from equilibrium.
Near-equilibrium Thermodynamics – linear analysis of irreversible processes.
Far-from-equilibrium Thermodynamics – nonlinear analysis of irreversible processes.

From this base, over the years, other variations of thermodynamics have come into their own as: chemical thermodynamics, thermal physics, atmospheric thermodynamics, economic thermodynamics, environmental thermodynamics, black hole thermodynamics, and others.


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While dealing with processes in which systems exchange matter or energy, classical thermodynamics is not concerned with the rate at which such processes take place, termed kinetics. For this reason, the use of the term "thermodynamics" usually refers to equilibrium thermodynamics. In this connection, a central concept in thermodynamics is that of quasistatic processes, which are idealized, "infinitely slow" processes. Time-dependent thermodynamic processes are studied by non-equilibrium thermodynamics.

In Thermodynamics, there are four laws of very general validity, and as such they do not depend on the details of the interactions or the systems being studied. This means they can be applied to systems about which one knows nothing other than the balance of energy and matter transfer with the environment. Examples of this include Einstein's prediction of spontaneous emission around the turn of the 20th century and the current research into the thermodynamics of black holes.

It is important to remember that the laws of thermodynamics are only statistical generalizations. That is, they simply describe the tendencies of macroscopic systems. On the quantum level, the laws of thermodynamics often break down. Furthermore, as evidenced by Maxwell's demon, it is theoretically possible to specifically engineer a quantum system to break the laws of thermodynamics. The first law of thermodynamics, however, i.e. the law of conservation, has become the most sound of all laws in science. Its validity has never been disproved.
source: from wikpidea
i will be back to discuss the section
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[محمد عمر]

hi dear students;
although there is no body still now came to discuss the section i will continue alone

[محمد عمر]

section 2 History
Most cite Sadi Carnot’s 1824 paper Reflections on the Motive Power of Fire as the starting point for thermodynamics as a modern science. Carnot defined "motive power" to be the expression of the useful effect that a motor is capable of producing. Herein, Carnot introduced us to the first modern day definition of "work": weight lifted through a height. The desire to understand, via formulation, this useful effect in relation to "work" is at the core of all modern day thermodynamics.

The name "thermodynamics", however, did not arrive until some twenty-five years later when in 1849, the British mathematician and physicist William Thomson (Lord Kelvin) coined the term ‘thermodynamics' in a paper on the efficiency of steam engines. In 1850, the famed mathematical physicist Rudolf Clausius originated and defined the term enthalpy H to be the total heat content of the system, stemming from the Greek word ‘enthalpein’ meaning to warm, and defined the term entropy S to be the heat lost or turned into waste, stemming from the Greek word ‘entrepein’ meaning to turn.

In association with Clausius, in 1871, a Scottish mathematician and physicist James Maxwell formulated a new branch of thermodynamics called Statistical Thermodynamics, which functions to analyze large numbers of particles at equilibrium, i.e. systems where no changes are occurring, such that only their average properties as temperature T, pressure P, and volume V become important.

Soon thereafter, in 1875, the Austrian physicist Ludwig Boltzmann formulated a precise connection between entropy S and molecular motion:


being defined in terms of the number of possible states [W] such motion could occupy, where k is the Boltzmann's constant. The following year, 1876, was a seminal point in the development of human thought. During this essential period, chemical engineer Willard Gibbs, the first person in America to be awarded a PhD in engineering (Yale), published an obscure 300-pg paper titled: On the Equilibrium of Heterogeneous Substances, wherein he formulated one grand equality, the Gibbs free energy equation, which gives a measure the amount of "useful work" attainable in reacting systems:


Building on these foundations, those as Lars Onsager, Erwin Schrodinger, and Ilya Prigogine, and others, functioned to bring these engine “concepts” into the thoroughfare of almost every modern-day branch of science.

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