Based on the experimental data obtained in the study of the surface tension of the indicated aqueous surfactant solution at 20°C, calculate the area occupied by one surfactant molecule and the thickness of the adsorption monolayer in two ways: graphical and analytical. For this:

Graphical way
1. Plot the surface tension isotherm σ= f(С)

2. Draw a graphical differentiation of the curve, find the value of the segment Z.

3. Calculate the amount of adsorption Г according to the equation Г= Z/RT.

4. Calculate the values ​​of G/C and build the adsorption isotherm in the coordinates of the linear form of the Langmuir equation S/G = f(C)

5. Determine graphically the values ​​of G∞ and K.

6. Calculate S0 and δ.

7 option. Surfactant - nonanoic acid.
C*104, mol/dm3 0.0 0.40 0.8 1.26 1.58 2.51 4.00 6.31
σ*103, J/m2 72.75 68.90 66.40 63.00 60.90 55.90 50.20 44.60

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