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Keywords:
Thermodynamic,
Equilibrium,
Ideal,
Density,
Friedmann
An equation, such as PV = nRT, which relates two or more of the quantities that describe the state of a system.
is any equation that relates the pressure, temperature, and specific volume of a substance. Property relations that involve other properties of a substance at equilibrium states are also referred to as equations of state.
an equation which relates the variables of state (T, P, V, and n)
the relation between the pressure and density of a given type of matter, which is an indication of how the matter resists squeezing. If the matter resists squeezing strongly (e.g., water), the equation of state is stiff; if it resists squeezing only weakly (e.g., air), the equation of state is soft.
A relationship between the state variables of the system. Simple systems in equilibrium are fully specified by two properties such as temperature and volume; all the other functions of state are functions of these. For an ideal gas, the equation of state is ; for an ideal paramagnet it is where is a constant.
the ratio of the pressure to the energy density in the dark energy or vacuum energy. Usually denoted by . For the cosmological constant w = -1.
the state of an ideal gas can be shown to be p=RT, where p is the pressure; is the specific volume; R is the specific gas constant; and T is the absolute temperature
An equation that describes the behavior of matter in a given state; the van der Waals equation describes the behavior of the gaseous state.
the relation that describes the state or condition of a material as determined by how the temperature, density, and pressure depend on each other in the material.
In physics and thermodynamics, an equation of state is a relation between state variables. More specifically, an equation of state is a thermodynamic equation describing the state of matter under a given set of physical conditions. It is a constitutive equation which provides a mathematical relationship between two or more state functions associated with the matter, such as its temperature, pressure, volume, or internal energy.
In cosmology, the equation of state of a perfect fluid is characterized by a dimensionless number w, equal to the ratio of its pressure p to its energy density ρ: w=p/\rho . It is closely related to the thermodynamic equation of state and ideal gas law. The equation of state is used to describe the evolution of a perfect fluid in a homogeneous isotropic universe, the Friedmann-Lemaître-Robertson-Walker universe.
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