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The molar gas constant (also known as the gas constant, universal gas constant, or ideal gas constant) is denoted by the symbol R or R. It is the molar equivalent to the Boltzmann constant , expressed in units of energy per temperature increment per amount of substance , rather than energy per temperature increment per particle .
Some constants, such as the ideal gas constant, R, do not describe the state of a system, and so are not properties. On the other hand, some constants, such as K f (the freezing point depression constant, or cryoscopic constant ), depend on the identity of a substance, and so may be considered to describe the state of a system, and therefore ...
R is the gas constant, which must be expressed in units consistent with those chosen for pressure, volume and temperature. For example, in SI units R = 8.3145 J⋅K −1 ⋅mol −1 when pressure is expressed in pascals, volume in cubic meters, and absolute temperature in kelvin. The ideal gas law is an extension of experimentally discovered ...
While the values of the physical constants are independent of the system of units in use, each uncertainty as stated reflects our lack of knowledge of the corresponding value as expressed in SI units, and is strongly dependent on how those units are defined. For example, the atomic mass constant is exactly known when expressed using the dalton ...
It is common, especially in engineering and meteorological applications, to represent the specific gas constant by the symbol R. In such cases, the universal gas constant is usually given a different symbol such as ¯ or to distinguish it. In any case, the context and/or units of the gas constant should make it clear as to whether the universal ...
In physics, the thermal equation of state is a mathematical expression of pressure P, temperature T, and, volume V.The thermal equation of state for ideal gases is the ideal gas law, expressed as PV=nRT (where R is the gas constant and n the amount of substance), while the thermal equation of state for solids is expressed as:
Technical literature can be confusing because many authors fail to explain whether they are using the ideal gas constant R, or the specific gas constant R s. The relationship between the two constants is R s = R / m, where m is the molecular mass of the gas. The US Standard Atmosphere (USSA) uses 8.31432 m 3 ·Pa/(mol·K) as the value of R.
In other words, that theory predicts that the molar heat capacity at constant volume c V,m of all monatomic gases will be the same; specifically, c V,m = 3 / 2 R. where R is the ideal gas constant, about 8.31446 J⋅K −1 ⋅mol −1 (which is the product of the Boltzmann constant k B and the Avogadro constant).