If the temperature of air in the room is raised from 25°C to 35°C, by what factor would the diffusivity of a gas in the air increase? Is dispersion just another name for diffusion? Can you have...

If the temperature of air in the room is raised from 25°C to 35°C, by what factor would the diffusivity of a gas in the air increase?

Is dispersion just another name for diffusion? Can you have dispersion without any flow whatsoever? Can you have diffusion without any flow whatsoever?