Thermodynamics

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.

Applications of First Law of Thermodynamics

:* An Isochoric process is where the volume is held constant, meaning that the work will be zero. Additionally, any energies transferred to the system externally are transferred into internal energy. An example would be to throw a container of gas into heat. In an ideal world, the container will not expand and the gas inside will gain interal energy. In reality, the container will burst in some moment in time.

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:* An Isothermal process occures at a constant temperature. In this process, the internal energy remains zero and this means that any energy transfer must equal to work.

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:* An Isobaric process is held at constant pressure. An example would be to let a piston free which exerts a forces itself on a chamber of gas.

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:* An Adiabatic process is when the heat change and enthalpy in a gas are equal to zero. In this case, the product of both the volume and pressure of the gas will remain constant. This means that either pressure will increase while the volume decreases or vice versa.

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