Estimate the time needed for a glycine molecule to diffuse a distance of $16$ mm in water at $20$C$$C if its concentration varies over that distance from $1\mathrm{.}40$ mol$/$m$3$mol$/$m$3$ to $0\mathrm{.}70$ mol$/$m$3$mol$/$m$3?$Compare this "speed" to its rms $($thermal$)$ speed. The molecular mass of glycine is about $75$ uu$.$