How is the molar volume of a gas calculated?

The molar volume of a gas is defined as the volume occupied by one mole of a gas at standard temperature and pressure (STP), which is commonly taken to be 0 degrees Celsius and 1 atmosphere of pressure. Under these conditions, the molar volume of an ideal gas is approximately 24 dm³ (or 24 liters).

The reasoning behind the correct choice is that it directly correlates the number of moles of gas with the volume it occupies using the standard molar volume. By multiplying the amount of gas in moles by 24 dm³, you can accurately determine the volume that the gas would occupy at STP. This relationship is foundational in stoichiometry and gas calculations in chemistry, allowing you to convert between the number of moles and the volume of a gas.

Thus, using this formula provides a straightforward method for understanding how many liters of gas are present for a given amount in moles, making it a crucial concept in chemistry.