When a front passes over an area, it means a change in the weather. Many fronts cause weather events such as rain, thunderstorms, gusty winds, and tornadoes. At a cold front, there may be dramatic thunderstorms. At a warm front, there may be low stratus clouds. Usually, the skies clear once the front has passed.
an increase in concentration increases the rate of the reaction. This is because there are more reactant particles available which allows for more effective collisions between reactant particles in a given period of time. More effective collisions bring about a faster rate of reaction.