Diffusion distance question

Question

Diffusion is the movement of molecules from one location to another. The time t (in seconds) it takes molecules to diffuse a distance of x centimeters is given by t=x22D, where D is the diffusion coefficient. The diffusion coefficient for a drop of ink in water is about 10−5 square centimeters per second. How long will it take the ink to diffuse 1 micrometer (10−4 centimeter)? Write your answer as a decimal.

Answer 1

We will substitute the values in for x and D:

t = 10^-4 cm(22)(10^-5cm) = 2.2^-13seconds