Gas Adsorption Surface Area Measurement · Physics Brawl 2025 #8
Physics · thermodynamics
Problem
In the examination of the surface area of porous or powdery materials, gas adsorption on the material can be utilized. A sample with a skeletal density of 1200 kg·m⁻³ and mass 59 mg is placed into a 15 ml pipette, and the air is evacuated to create a very high vacuum. Then, a 1.1×10−3 mol of nitrogen gas is introduced. After reaching equilibrium, the pressure is measured to be 0.15 bar. What is the surface area of the sample, assuming that the area of one adsorbed molecule is 0.16 nm²? The whole experiment is conducted at the temperature of liquid nitrogen T=−196°C.