Concentration Of Sodium Dodecyl Re

Objective In this experiment, the critical micelle concentration of sodium dodecyl sulfate (SDS) is determined by the conductance method.

Procedure In this experiment, a series of SDS solutions at various concentrations are tested for their conductance at two different temperatures, 25 °C and 50 °C. For detailed procedure, refer to the lab manual (J. F. Wójcik and T. S. Ahmadi, Experimental Physical Chemistry, 2015; p.125-129.).

Data Sodium dodecyl sulfate has a molecular weight of 288.372 g/mol, with a density of 1.01 g/cm³. The melting point of SDS is in the ranges of 204 -205.5 °C. In this experiment, 8.6151 g of SDS was weighed to make a 500-mL 0.06 M solution.

Before any calculations, all the conductance data were baseline corrected with the conductance of pure water at each temperature. To

According to a literature Domínguez, A, the critical micelle concentration of SDS at 25 °C determined by the conductance method is 0.0080 M. Compared to the literature value, the experimental value has a percent error of 8.25%. The discrepancies between the two values could be a result of slightly different methods, the presence of impurities, or the slight change in concentrations due to evaporations of the solvent. When impurities are present in the solution, they can affect the ability for SDS molecule to form micelles. This can affect the critical micelle concentration. Note that the critical micelle concentration of SDS at 25 °C is lower than at 50 °C. This is most likely due to the fact that at higher temperatures, there is more movement between molecules, which makes them more difficult to come together and form a proper micelle structure. Therefore, more SDS molecules are needed in the solution so that they can form micelle at higher temperature, explaining why the CMC at 50 °C is higher. There are no known literature value for CMC of SDS at 50