In the Stokes-Einstein relation, which parameter increases the diffusion coefficient when raised?

In the Stokes-Einstein relation, which parameter increases the diffusion coefficient when raised?

• A. Radius
• B. Viscosity
• C. Pressure
• D. Temperature

Answer: (D)

Diffusion grows when temperature rises because molecules have more kinetic energy and move more vigorously, helping particles diffuse faster through the fluid. In the Stokes-Einstein relation for a spherical particle in a viscous fluid, D equals k_B T divided by 6π η r. This shows D is directly proportional to temperature and inversely proportional to both the solvent’s viscosity and the particle’s radius. So increasing temperature raises D, while increasing radius or viscosity lowers D. Pressure isn’t part of this expression, so it doesn’t directly change D (though it could affect viscosity or density, which would then influence D indirectly).

Diffusion grows when temperature rises because molecules have more kinetic energy and move more vigorously, helping particles diffuse faster through the fluid. In the Stokes-Einstein relation for a spherical particle in a viscous fluid, D equals k_B T divided by 6π η r. This shows D is directly proportional to temperature and inversely proportional to both the solvent’s viscosity and the particle’s radius. So increasing temperature raises D, while increasing radius or viscosity lowers D. Pressure isn’t part of this expression, so it doesn’t directly change D (though it could affect viscosity or density, which would then influence D indirectly).