Mechanical work pressure-volume energy

Pressure-Volume Energy Produces Mechanical Work (MW) (Lowering Pressure Through the Transition Zone Drives Contraction)... 

Thennal equilibrium means free transfer (exchange) of energy in the fonn of heat, mechanical (liydrostatic) equilibrium means free transfer of energy in the fonn of pressure-volume work, and material equilibrium means free transfer... 

These thermodynamic concepts denote the energy which is bound during the formation of a given compound from its constituent elements at constant volume (energy of formation) or at constant pressure (enthalpy of formation, which includes the mechanical work performed at the standard state44) (25 °C = 77°F and a pressure of 1 bar). The data are tabulated in accordance with thermodynamic convention if the formation of a compound from its elements is... 

The relationship dw = —PdF reflects the fact that when mechanical work is done on the system, its volume decreases. Otherwise stated, if the volume of the system increases during a change in state, the system must do work against the surrounding pressure, which leads to a net loss in its internal energy. 

Energy can be converted from one form to another, but it cannot be created or destroyed (first law of thermodynamics). In chemistry we are concerned mainly with thermal energy, electrical energy, and mechanical energy, which is usually associated with pressure-volume work. 

In order to provoke spontaneous processes, we will introduce into the solution some amoimt of heat Q, i.e., we will increase the kinetic energy of its components. Under conditions of isolation and constancy of the ambient pressure part of this excess energy will go for the increase of the solution volume by AV values. Therefore, part of the heat will come back in the form of mechanical work (expansion work)... 

The work W, which is energy per unit time, can be divided into purely mechanical shaft work identified with a rotating shaft crossing the control surface, and the pressure-volume work, which has been included in the enthalpy term H in Eq. (2.7-6). By convention, work done by the fluid upon the surroundings, i.e., work out of the... 

As energy is conserved, the change of the internal energy t/ of a system equals the heat dQ absorbed and the mechanical work dW done to the system, dU =dQ + dW. When the volume of the system changes by dV under the pressure P, the mechanical work done to the system is given by... 

Carnot cycle The idealized reversible cycle of four operations occurring in a perfect heat engine. These are the successive adiabatic compression, isothermal expansion, adiabatic expansion, and isothermal compression of the working substance. The cycle returns to its initial pressure, volume, and temperature, and transfers energy to or from mechanical work. The efficiency of the Carnot cycle is the maximum attainable in a heat engine. It was published in 1824 by the French physicist Nicolas L. S. Carnot (1796-1832). See Carnot s principle. 

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