85. Solving a chemistry problem

44. When measuring the surface tension of aqueous solutions of propionic acid at 20 0C, the following values were obtained:
Concentration, mol/l 0.1 0.238 0.952 2.0
Surface tension, ∂in/cm 65.5 60.0 45.66 38.75

Based on these data, plot σ = f(С) and Г= f(С),
1/Г=f(1/C) and determine 1/Г and Г ; calculate the surface area of the adsorbent (cm²) occupied by one adsorbent molecule.