Give three examples from our daily life to show how important it is for gases to diffuse quickly.

Diffusion is the process by which molecules of a gas move
from a more concentrated state to a less concentrated state because they are constantly
in motion.  All gases are constantly in motion and this is the basis of the kinetic
molecular theory.  You may experience this when someone standing near you uses perfume
or a spray cologne and you quickly detect the odor of the
perfume.

Three examples that come to mind are first the
detection of leaks of natural gas when you smell the odorant that is added to natural
gas. Natural gas has no odor of its own  and so a strongly smelling sulfur compound is
added.  This way if a leak occurs it can be quickly detected and fixed, minimizing the
possibility of an explosion.

A second example would be the
release of oxygen from plants during photosynthesis.  This oxygen is necessary for all
animal life on earth and if it did not quickly diffuse some areas of the world would
have high levels of oxygen while other areas (such as deserts) would have almost
none.

A third example is the exhaust from automobiles. This
exhaust contains, along with carbon dioxide and water, many other compounds, some of
which are harmful and even potentially fatal, to people. Because of diffusion, the gases
in the exhaust quickly mix with the surrounding air and drop to levels that are no
longer dangerous to us.