When studying the adsorption of stearic acid from its s

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When studying the adsorption of stearic acid from its solutions in n-hexane of various concentrations on a steel powder, the results were obtained:
c × 105, mol / L 1 2 4 7 10 15 20 25
A × 103, kg / kg 0.786 0.864 1.00 1.17 1.30 1.47 1.70 1.70
Calculate the specific surface area of the steel powder by taking the area of 1 stearic acid molecule in a saturated monolayer of 0.20 nm2.