A beaker of water at contains dissolved potassium chloride (KCl

PHYSICS · Subjective · Fermi University Physics · Condensed Matter, Materials & Soft Matter · Soft condensed matter · Soft condensed matter

Soft Matter at the Thermal Scale, Ch Forces between colloids and the stability of a dispersion

Problem

A beaker of water at

298\,\mathrm{K}

contains dissolved potassium chloride (KCl, a 1:1 salt) at a concentration of

50\,\mathrm{mM}

. Using the working formula

\lambda_{\rm D} = 0.304\,\mathrm{nm}/\sqrt{c/\mathrm{M}}

for a 1:1 salt in water at

298\,\mathrm{K}

, calculate the Debye screening length.