The gas constant is a physical constant denoted by R and is expressed in terms of units of energy per temperature increment per mole. It is also known as the ideal gas constant or molar gas constant or universal gas constant. The gas constant value is equivalent to the Boltzmann constant but expressed as the pressure-volume product instead of energy per increment of temperature per particle.
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Gas Constant Value
In physics, the gas constant is the proportionality constant used to relate the energy scale to the temperature scale, when one mole of particles at a defined temperature is considered. The ideal gas constant is the combination of Boyle’s law, Avogadro’s number, Charles’s law and Gay-Lussac’s law. Thus, the gas constant R can be given as –
Gas constant R = 8.3144598(48) J⋅mol−1⋅K−1
The digits inside the parentheses are the uncertainty in the measurement of the gas constant value.
Read More: Boltzmann Constant
Gas Constant in Different Units
The gas constant is inversely used in diverse disciplines. Hence, it is expressed in many units. Some gas constant values in different units are listed below-
| Gas Constant Value | Units |
| 8.3144598(48) | J⋅K−1⋅mol−1 |
| 8.3144598(48)×103 | amu.m2.s-2.K-1 |
| 8.3144598(48)×10−2 | L.bar.K-1.mol-1 |
| 8.3144598(48) | m3.Pa.K-1.mol-1 |
| 62.363577(36) | L.Torr.K-1.mol-1 |
| 1.9872036(11)×10−3 | kcal.K-1.mol-1 |
| 8.2057338(47)×10−5 | m3.atm.K-1.mol-1 |
| 0.082057338(47) | L.atm.K-1.mol-1 |
R Constant for Atm
In the US Standard Atmosphere the R constant for atm is given as
R = 8.31432×103 N⋅m⋅kmol−1⋅K−1.
Read More: R Constant
Specific Gas Constant
The ratio of the molar gas constant(R) to the molar mass(M) of the gas mixture is called The specific gas constant. Denoted by Rspecific and mathematically expressed as –
Dimensions
Using the ideal gas equation PV = n RT. The gas constant R can be expressed as-
Where,
- P is the pressure.
- V is the volume,
- n is the number of moles of the given substance
- T is the temperature.
Thus, writing pressure as force per unit area we can derive the dimensional expression for R as-
Area and Volume can be expressed in terms of length as volume=(length)3 and area = (length)2
Thus we get-
Since force times length is work we get-
Thus gas constant can be interpreted as work per degree per mole.
Hope you have understood what is gas constant. the gas constant value in different units along with the ideal gas formula and Application in physics.
Physics Related Topics:
| Stefan-Boltzmann Constant |
| Faraday Constant |
| Value of Gravitational Constant |
| Rydberg Constant |
To know more about Boyle’s law, click on the video below
Frequently Asked Questions – FAQs
What is the formula to calculate the specific gas constant?
What is the value of Gas constant (R)?
Write the formula for an ideal gas equation.
What is a gas constant also known as?
The ideal gas constant is the combination of which laws?
- Boyle’s law
- Charles’s Law
- Gay-Lussac’s law
- Avogadro’s number
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