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How to Calculate the Molar Volume of an Ideal Gas

In physics, the ideal gas approximation assumes no interactions between molecules of the gas. The majority of real gases obey the ideal gas law. This law sets the relation between the gas volume, temperature and pressure. The molar volume represents the volume occupied by one mole of the gas under the given temperature and pressure. Use the following equation derived from the gas law to calculate the molar volume: (Temperature times gas Constant) divided by pressure.

Things You'll Need

Calculator

Instructions

- 1
  Convert temperature to Kelvin (K); add the number 273 to the temperature in Celsius. For example, 30 degrees of Celsius converts to 30 plus 273, or 303 K.
- 2
  Get the universal gas constant value (see Resources), which is 0.08206. Note that the constant units allow you to express the pressure in atmospheres (atm) and the volume in liters.
- 3
  Multiply by the universal gas constant 0.08206 and the temperature. In this example, 0.08206 times 303 equals 24.864.
- 4
  Divide the product by the pressure to calculate the molar volume. In this example, if the pressure is two atmosphere (atm), then the molar volume is 24.864 divided by 2, or 12.432 liters.

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