The pressure of 1 mol of gas is decreased to 0.5 atm at 273 K. What happens to the molar volume of the gas under these conditions?

At a fixed temperature, the ideal gas law gives molar volume as Vₘ = RT/P, so molar volume is inversely proportional to pressure. Decreasing the pressure from 1 atm to 0.5 atm halves the pressure, which doubles the molar volume. Therefore, the molar volume is doubled.

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