The compression factor (compressibility factor) for onemole of a van d

1.	The compression factor (compressibility factor) for onemole of a van der Waals' gas at 0°C and 100 atm pressureis found to be 0.5. Assuming that the volume of a gasmolecule is negligible, calculate the van der Waals'constant 'a.(2001)
Answer» We know that, Compressibility factor, Z = PV/RT 0.5 = 100 V/0.082 273 ∴ V = 0.1117L NOTE :Further when volume of a gas molecule is negligible, van der Waal’s equation becomes (P + a/V²) (V - 0) = RT Or PV = RT – a/V or a = RTV – PV² Substituting the values A = (0.082 * 0.1119 273) – (100 0.1119 * 0.1119) = 1.253 atm L²mol-²

The compression factor (compressibility factor) for onemole of a van der Waals' gas at 0°C and 100 atm pressureis found to be 0.5. Assuming that the volume of a gasmolecule is negligible, calculate the van der Waals'constant 'a.(2001)

Answer»

We know that, Compressibility factor, Z = PV/RT

0.5 = 100 *V/0.082 *273

∴ V = 0.1117L

NOTE :Further when volume of a gas molecule is negligible, van der Waal’s equation becomes

(P + a/V²) (V - 0) = RT

Or PV = RT – a/V or a = RTV – PV²

Substituting the values

A = (0.082 * 0.1119 *273) – (100 * 0.1119 * 0.1119)

= 1.253 atm L²mol-²