the describtion of thermodynamic process?

Question

such as isobaric ,isothemic ,and isovolumetric

Answer 1

Thermodynamics, field of physics that describes and correlates the physical properties of macroscopic systems of matter and energy. The principles of thermodynamics are of fundamental importance to all branches of science and engineering.

A central concept of thermodynamics is that of the macroscopic system, defined as a geometrically isolable piece of matter in coexistence with an infinite, unperturbable environment. The state of a macroscopic system in equilibrium can be described in terms of such measurable properties as temperature, pressure, and volume, which are known as thermodynamic variables. Many other variables (such as density, specific heat, compressibility, and the coefficient of thermal expansion) can be identified and correlated, to produce a more complete description of an object and its relationship to its environment.

When a macroscopic system moves from one state of equilibrium to another, a thermodynamic process is said to take place. Some processes are reversible and others are irreversible. The laws of thermodynamics, discovered in the 19th century through painstaking experiment, govern the nature of all thermodynamic processes and place limits on them.

Answer 2

A thermodynamic process may be defined as the energetic evolution of a thermodynamic system proceeding from an initial state to a final state. Paths through the space of thermodynamic variables are often specified by holding certain thermodynamic variables constant. It is useful to group these processes into pairs, in which each variable held constant is one member of a conjugate pair.

The pressure-volume conjugate pair is concerned with the transfer of mechanical or dynamic energy as the result of work.

* An isobaric process occurs at constant pressure. An example would be to have a movable piston in a cylinder, so that the pressure inside the cylinder is always at atmospheric pressure, although it is isolated from the atmosphere. In other words, the system is dynamically connected, by a movable boundary, to a constant-pressure reservoir.

* An isochoric process is one in which the volume is held constant, meaning that the work done by the system will be zero. It follows that, for the simple system of two dimensions, any heat energy transferred to the system externally will be absorbed as internal energy. An isochoric process is also known as an isometric process. An example would be to place a closed tin can containing only air into a fire. To a first approximation, the can will not expand, and the only change will be that the gas gains internal energy, as evidenced by its increase in temperature and pressure. Mathematically, δQ = dU. We may say that the system is dynamically insulated, by a rigid boundary, from the environment.

The temperature-entropy conjugate pair is concerned with the transfer of thermal energy as the result of heating.

* An isothermal process occurs at a constant temperature. An example would be to have a system immersed in a large constant-temperature bath. Any work energy performed by the system will be lost to the bath, but its temperature will remain constant. In other words, the system is thermally connected, by a thermally conductive boundary to a constant-temperature reservoir.

* An isentropic process occurs at a constant entropy. For a reversible process this is identical to an adiabatic process (see below). If a system has an entropy which has not yet reached its maximum equilibrium value, a process of cooling may be required to maintain that value of entropy.

* An isenthalpic process introduces no change in enthalpy in the system.

* An adiabatic process is a process in which there is no energy added or subtracted from the system by heating or cooling. For a reversible process, this is identical to an isentropic process. We may say that the system is thermally insulated from its environment and that its boundary is a thermal insulator. If a system has an entropy which has not yet reached its maximum equilibrium value, the entropy will increase even though the system is thermally insulated.

The above have all implicitly assumed that the boundaries are also impermeable to particles. We may assume boundaries that are both rigid and thermally insulating, but are permeable to one or more types of particle. Similar considerations then hold for the (chemical potential)-(particle number) conjugate pairs.

Answer 3

WE know the gas equation is PV = mu RT.

There are three variables in this equation.

To find the behavior of the gas we fix any one and find the relation between the other two.

If we fix the temperature, then pressure varies with volume. The process is called isothermal. Iso means same.

If we fix the volume, pressure varies with temperature. The process is called isochoric or (isovolume)

If we fix the pressure, volume varies with temperature. The process is called isobaric. (Bar is the unit of pressure).

There is one more process called adiabatic in which pressure volume and temperature, change. This process takes place when neither heat enters or leaves the given subtance.

Answer 4

Isobaric : Pressure remains constant

Isothermal : Temperature remains constant

Isovolumetric : Volume remains constant