98. Solving a chemistry problem

79. Determine the sign of the charge and the value of the zeta potential of nanoparticles of a quartz suspension in water (the thickness of the diffuse layer is much greater than the particle size). During electrophoresis, particles move towards the anode. Over a time of 3900 s, the observed boundary has shifted by a distance of 5.00 cm, the voltage gradient of the external field is 20.0 Vm, the relative dielectric constant of the medium is 80.16, and the viscosity is 1.002 mPa s.