41. Solution to Chemistry Problem

7. Based on the data on the dependence of the surface tension of aqueous solutions of surfactants on concentration at a temperature of 293 K (Table 1), complete the following tasks:
• calculate, using the analytical method, the value of Gibbs adsorption G;
• plot the adsorption isotherm;
• plot the surface tension isotherm σ=f(C) and determine the value of surface activity;
• perform a graphical differentiation of the surface tension isotherm and calculate the value of adsorption;
Draw conclusions about the accuracy of the analytical and graphical methods for calculating the adsorption value G.
Option 7
Surfactant Nonanoic acid CH3(CH2)7COOH
Concentration C*103, kmol/m3 0.000 0.040 0.080 0.126 0.300 0.400 0.500 0.630
Surface tension 6*103, J/m2 72.75 65.00 58.00 52.00 43.00 40.00 38.00 35.00