Question

Molar volume is the volume occupied by 1 mol of any (ideal) gas at standard temperature and pressure (STP : 1 atmospheric pressure, 0 °C). Show that it is 22.4 litres

Answer 1

Given:

For an ideal gas at STP:
Pressure, P = 1 atm = 1.013 × 10⁵ Pa
Temperature, T = 0 °C = 273 K
Number of moles, n = 1 mol
Gas constant, R = 8.314 J mol⁻¹ K⁻¹

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Step 1: Use the ideal gas equation

PV = nRT

For 1 mole of gas:

PV = RT

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Step 2: Substitute the values

V = RT / P

V = (8.314 × 273) / (1.013 × 10⁵)

V = 0.0224 m³

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Step 3: Convert cubic metres into litres

1 m³ = 1000 L

V = 0.0224 × 1000

V = 22.4 L

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Final Answer:

The molar volume of an ideal gas at STP is:
22.4 litres