Estimate the time needed for a glycine molecule (see Table 13-4) to diffuse a distance of 25m

Estimate the time needed for a glycine molecule (see Table 13-4) to diffuse a distance of 25μm in water at 20°C if its concentration varies over that distance from 1.00mol / m3 to 0.50 mol / m3? Compare this "speed" to its rms (thermal) speed. The molecular mass of glycine is about 75 u.

Table 13-4

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TABLE 13-4 Diffusion Constants, D (20°C, 1 atm) Diffusing Molecules Medium D (m2/s) 6.3 x 105 1.8 x 10-5 H2 Air O2 O2 Glycine (an amino acid) Water Air 100 x 101" Water 95 x 10-11 Blood hemoglobin Water DNA (mass 6 x 10 u) Water 6.9 x 10-11 0.13 x 10-11