100. Solving a chemistry problem

719. Commercial colloidal quartz (SiO2, trademark Min-U-Sil), fractionated to an equivalent particle radius of 0.3-0.5 µm, shows an electrophoretic mobility of -0.045 mm2 / (V * s) in a solution of 1 * 10-2 mol / l NaCl at 25.0 °С (pH 9). Calculate DEL thickness and zeta potential. Find the necessary characteristics of the NaCl solution from the reference empirical equations: er = 78.36 - 13.8С 0.98С2; n = 0.8903×(1 0.0793C), where C is in mol/l, n is in cps.