Gas Constant - Definition, Value, Units, FAQs

Gas constant is used is a fundamental value that relates the gas to its temperature. It is used in Ideal gas equation, which helps us to understand how gas behaves under varying conditions. The gas constant connects the macroscopic properties of a gas (such as pressure, and volume) and the microscopic properties of the gas (such as molecule movement). Let's discuss the Gas constant in detail.

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This Story also Contains

1. What is Gas Constant?
2. Value of Gas Constant
3. Units of Gas Constant
4. Applications of the Gas Constant

What is Gas Constant?

A gas constant is a physical phenomenon defined by R and expressed in units of energy by the increase in temperature per molecule. It is also known as an Ideal gas constant or molar gas constant or even universal gas constant. The fixed amount of gas is equivalent to the constant durability of Boltzmann but is expressed as a product of volume pressure instead of the force with each temperature increase of the particles.

Continuous Gas Value

In physics, a constant flow of gas is used to associate the energy scale with a temperature scale, considering a single molecular molecule at a specified temperature. The ideal gas time is a combination of Boyle's law, Avogadro's number, Charles' law, and Gay-Lussac's law.

Value of Gas Constant

The factor “R” in the ideal gas law equation is known as the “gas constant”. The pressure times the volume of a gas divided by the number of moles, moles, and the temperature of the gas is always equal to a constant number.

Its value depends on the units used, but in the most commonly used units, it is:

1. $R=8.314 \mathrm{~J} /(\mathrm{mol} \cdot \mathrm{K})$ (Joules per mole per Kelvin) in SI units.

This is the most commonly used form in scientific contexts,

where:

• J (Joules) is the unit of energy
• mol refers to the amount of substance in moles
• K is the unit of temperature (Kelvin)

2. $\mathbf{R}=0.0821 \mathrm{~L} \cdot \mathrm{~atm} /(\mathrm{mol} \cdot \mathrm{K})$ in units of liter-atmosphere per mole per Kelvin.

This unit is often used in Chemistry, particularly in problems involving gases at standard conditions or in equations where pressure is given in atmospheres and volume in liters.

Units of Gas Constant

The gas constant R is the proportionality constant that relates the energy scale in thermodynamic equations, particularly in the equation of state for gases.

The gas constant can be expressed in various units depending on the system of measurement:
1. In Joules per mole per Kelvin (J/mol-K), as it is used in the SI system.
2. In liter-atmospheres per mole per Kelvin (L•atm/mol-K) for gas law calculations in terms of pressure in atmospheres and volume in liters.

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Relationship with Boltzmann Constant

The universal gas constant can be related to the Boltzmann constant (k), which applies to individual gas molecules, by the following relationship:

$$
R=N_A \cdot k
$$
Where:

• $N_A$ is Avogadro's number (the number of particles per mole, approximately $6.022 \times 10^{23}$ )
• $k$ is the Boltzmann constant (approximately $1.38 \times 10^{-23} \mathrm{~J} / \mathrm{K}$ )

What is an ideal gas?

An ideal gas is a theoretical gas formed by a group of randomly charged particles that meet only in an elastic collision. An ideal gas is one that follows the gas laws at all conditions of temperature and pressure. The gas needs to completely abide by the kinetic-molecular theory.

One of the most important equations involving the gas constant is the Ideal gas law, which states:

$$
P V=n R T
$$
Where:
$P$ is the pressure of the gas (in atmospheres or Pascals)
$V$ is the volume of the gas (in liters or cubic meters)
$n$ is the number of moles of gas
$R$ is the gas constant
$T$ is the temperature of the gas (in Kelvin)

Applications of the Gas Constant

Thermodynamics: In thermodynamic processes, R is used in calculating entropies and the Gibbs free energy.

Physical Chemistry: It is used in determining gas behavior in reactions and characteristics such as equilibrium constant and coefficient, as well as reaction rate.

Boltzmann's Distribution: It is useful in understanding ways energy might be spread out in systems at equilibrium, at different temperatures, and in the use of statistical mechanics.