One of the simplest examples of diffusion in everyday use is when perfume is sprayed and dispersed across a room. At first, perfume molecules are concentrated in the sprayer and dispersed across the room. However, as the perfume particles travel and collide, they disperse across the room, allowing the perfume to be detected even at a distance from the source.
2.5.1 Diffusion Process Explained by Kinetic Particle Theory
When two different gases come into contact, their particles begin to move together. Because of their kinetic energy, each type of a gas particle moves randomly in all directions. The random motion of these particles ensures that the particles from each of the two gases move into the other gas's space. This random and constant motion causes the gases to spread and mix up. The gas particles change direction as they move and collide with each other. As they change direction,
they spread out and move through the space available to them. As time goes on, this random motion causes the particles to spread out evenly across the space. Eventually, the concentration of both types of gas particles is uniform across the entire space, and equilibrium is achieved.
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2.5.2 Factors affecting diffusion
The rate of diffusion, the process by which molecules spread from areas of high concentration, is affected by several factors, including molecular weight and temperature.
Molecular weight
According to Graham's law of diffusion
The rate of diffusion is inversely proportional to the square root of the molar mass of the gas particles.