When the number of molecules, atoms, or ions of a particular type (here we consider H ions) is in the hundreds of millions, we can confidently speak of concentrations and analyze an average behavior. a. True
b. False

True.

Explanation:

When the number of molecules, atoms or ions of any element is in the hundreds of millions, we can safely speak of concentrations and analyze a standard behavior, and can even specify the different dilutions used, if there are dilutions. This allows analyzes to be clearly understood by any individual. However, it is not possible to do this if the number of molecules, atoms and ions is very small.

answer: the rate of diffusion increases with increase in temperature.

increase in temperature, increases the molecular/particles speed (kinetic energy. diffusion means movement of particles through the material.

generally, the heavier the particle the more it interacts with the environment and more the temperature matters. so higher temperature results in higher diffusion.