Ideal Gas Law (PV = nRT): Derivation and Numerical Values of R - Chemistry Notes (2024)

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Ideal Gas Law (PV = nRT): Derivation and Numerical Values of R - Chemistry Notes? ›

The ideal gas law (in terms of moles) is PV = nRT. The numerical value of R in SI units is R = N_Ak = (6.02 × 10²³ mol⁻¹)(1.38 × 10⁻²³ J/K) = 8.31 J/mol · K. You can use whichever value of R is most convenient for a particular problem.

The ideal gas law can be rearranged to solve for R, the gas constant. Under the initial conditions, R=PiViniTi and under final conditions, R=PfVfnfTf. Since both expressions are equal to R, they are equal to each other. This equation is typically used when one or more of the variables is constant.

The ideal gas law is PV = nRT, where n is the number of moles, and R is universal gas constant. The value of R depends on the units involved, but is usually stated with S.I. units as: R = 8.314 J/mol. It is just a constant to use in the equation.

The ideal gas law states that the product of the pressure and the volume of one gram molecule of an ideal gas is equal to the product of the absolute temperature of the gas and the universal gas constant.

The gas constant value is given by R = 8.3144598(48) J⋅mol^−1⋅K^−1.

The ideal gas equation is formulated as: PV = nRT. In this equation, P refers to the pressure of the ideal gas, V is the volume of the ideal gas, n is the total amount of ideal gas that is measured in terms of moles, R is the universal gas constant, and T is the temperature.

The ideal gas constant, also known as the molar gas constant, is expressed as R within the formula for the ideal gas law, PV=nRT. The ideal gas constant is the same for all gases but can vary based on which units are being used, the most common expressions are R = 0.0821 (L • atm/ mol • K) OR R = 8.31 (J/ mol • K).

To decide which R value to use in a given situation, you have to look at both the units of the other values involved in the calculation and the units you are trying to solve for. Once you've figured both the units out, you have to choose whichever R value will give you the correct units in your calculation.

Many gases such as nitrogen, oxygen, hydrogen, noble gases, some heavier gases like carbon dioxide and mixtures such as air, can be treated as ideal gases within reasonable tolerances over a considerable parameter range around standard temperature and pressure.

The value of the gas constant 'R' depends on the units used for pressure, volume and temperature. Prior to 2019, these were common values for the gas constant. R = 0.0821 liter·atm/mol·K. R = 8.3145 J/mol·K.

Why do we need R in ideal gas law? ›

The temperature value in the Ideal Gas Law must be in absolute units (Rankine [degrees R] or Kelvin [K]) to prevent the right-hand side from being zero, which violates the pressure-volume-temperature relationship.

The term ideal gas refers to a hypothetical gas composed of molecules which follow a few rules: Ideal gas molecules do not attract or repel each other. The only interaction between ideal gas molecules would be an elastic collision upon impact with each other or an elastic collision with the walls of the container.

An ideal gas is a theoretical gas composed of many randomly moving particles that are not subject to interparticle interactions. A real gas is simply the opposite; it occupies space and the molecules have interactions. This results in PV always equaling nRT.

In other words, an ideal gas would have identical particles of zero volume, with no intermolecular forces between them. The atoms or molecules in an ideal gas would also undergo elastic collisions with the walls of their container.