Final answer:
To find the root-mean-square distance travelled by particles, use the formula Xrms = √2Dt with known values of D and t.
Step-by-step explanation:
The root-mean-square (rms) distance travelled by particles in a random walk is calculated using the formula Xrms = √2Dt, where Xrms is the average root-mean-square distance, D is the diffusion constant, and t is the time.
The diffusion constant D depends on the specific molecule and medium, and its values for various substances can be found in tables, such as Table 12.2, in units of m²/s.
To calculate the root-mean-square distance for a particle, you would need to know both D and the time t that has elapsed during the diffusion process.