In a study of iron catalysts, the BET surface areas of a number of materials were determined using N2 or Ar physisorption near 80 K [71–73]. The Po values vary slightly because the bath temperature varied slightly around 77–80 K. What were the surface areas of the following solids based on the data provided below? What were the C values and the heats of adsorption for the initial monolayer of adsorbate? The heat of liquefaction for N2 is 1:34 kcal mole – 1
a) Silica (SiO2) (Cab-O-Sil, Grade 5, Cabot Corp) – N2 adsorption, assume Po = 725 Torr (760 Torr = 1 atm). (Ref. 73)