Question

The compression factor (compressibility factor) for one mole of a van der Waals' gas at 0°C and 100 atm pressure is found to be 0.5. Assuming that the volume of a gas molecule is negligible, calculate the van der Waals' constant 'a'

Answer 1

Given, compressibility factor (z) = 0.5

p = 100 atm, T = 0°C + 273 = 273 K

The van der Waals' equation for one mole of real gas :

If the volume of a gas molecule is negligible, then :

Now, compressibility factor for a mole of gas