0 Thermodvnamics By Sayantan Bhattacharya
Contents Laws of Thermodynamics Thermodynamics Processes Cas Equations Maxwell's relations. Carnot's cyde & Engine. Bc.
Laws Of Thermodynamics . First Law: The quantity of heat supplied to a system is capable of doing work, then the quantity of heat absorbed by the system is equal to the sum of the increase in the internal energy of the system, and the external work done by it.
s Second Law: (a)dausius statement:- Heat cannot flow from a cold body to a hot body without the performance of work by some external agency. . (b) Kelvin's statement:- It is impossible to obtain a continuous supply of energy by cooling a body below the coldest of its surroundings. .(c) Planck'sstatement:- It is impossible to extract heat from a single body and convert the whole of it into work.
Thermodynamic Processes A process is the path along which the system changes. constant temperature heat cannot take place between system and . " Isothermal process: Process which takes place at - Adiabaticprocess: Process during which transfer of " Isobaric process: Process which takes place at constant surrounding. pressure
Isochoric process Process which takes place at constant volume. Cydlic process: Process in which system comes back to itsinitial state after undergoing series of changes. Reversible process: Process during which the system always departs infinitesimally from the state of equilibrium i.e. its direction can be reversed at any moment.
Some terminologies. Open System: A system which can exchange both energy and matter with its surroundings. .Cosed System: A system which permits passage of energy but not mass, across its boundary. Isolated system: A system which can neither exchange energy nor matter with its surrounding. Surroundings: Part of the universe other than system, which can interact with it. Boundary: Anything which separates system from surrounding.
State variables: The variables which are required to be defined in order to define state of any system i.e. pressure, volume, mass, temperature, surface area, etc. . State Functions: Property of system which depend only on the state of the system and not on the path. Example: Pressure, volume, temperature, internal energy, enthalpy, entropy etc. Intensive properties: Properties of a system which do not depend on mass of the system i.e. Temperature, pressure, density, concentration, Extensive properties: Properties of a system which depend on mass of the system i.e. Volume, energy, enthalpy, entropy etoc.
Internal Energy (AU):- Sum total of kinetic and potential energies of atoms/ molecules constituting a system is called the internal energy of the system. (a) is taken as positive if the internal energy of the system increases. (b) AU is taken as negative if the internal energy of the system decreases. Heat:- Heat is the part of internal energy which is transferred from one body to another an account of the temperature difference.
Work:- Work is said to be done when a force acting on a system displaces the body in its own direction. dW Fax PdV (a) If the gas expands, work is said to be done by the system. In this case V> V, therefore, Wwill be positive. (b) If the gas is compressed, work is said to be done on the system. In this case h < h, therefore, work done is negative.
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