What is the volume, in liters, of one mole of an ideal gas at STP?

What is the volume, in liters, of one mole of an ideal gas at STP?

• A. 22.4
• B. 1.0
• C. 44.8
• D. 10.0

Answer: (A)

At STP, the volume of an ideal gas per mole comes from PV = nRT. With one mole, pressure 1 atm, temperature 273.15 K, and the ideal gas constant R ≈ 0.082057 L·atm/(mol·K), the volume is V = nRT/P = (1)(0.082057)(273.15)/1 ≈ 22.4 L. So one mole occupies about 22.4 liters at STP. This standard molar volume is a handy reference value; at room temperature (about 25°C) it’s closer to 24.0 L, and using slightly different pressure definitions (like 1 bar) gives a nearby number (about 22.7 L).

At STP, the volume of an ideal gas per mole comes from PV = nRT. With one mole, pressure 1 atm, temperature 273.15 K, and the ideal gas constant R ≈ 0.082057 L·atm/(mol·K), the volume is V = nRT/P = (1)(0.082057)(273.15)/1 ≈ 22.4 L. So one mole occupies about 22.4 liters at STP. This standard molar volume is a handy reference value; at room temperature (about 25°C) it’s closer to 24.0 L, and using slightly different pressure definitions (like 1 bar) gives a nearby number (about 22.7 L).