Why does the rate of most reactions decrease over time?
a) a decrease in reactant concentration reduces the frequency of successful collisions.
b) a decrease in temperature reduces the average kinetic energy of the particles.
c) an increase in product concentration interferes with the effectiveness of the catalyst.
d) an increase in pressure of the system reduces the movement and energy of particles.

ExplanaA) A decrease in reactant concentration reduces the frequency of successful collisions.  tion:

As a reactant gets used up, there are fewer molecules present to collide with others. A reaction depends on molecular collisions. When there are fewer collisions, the reaction slows down.

B) is wrong. A reaction is usually carried out at constant temperature,

C) is wrong. Not all reactions need catalysts.

D) is wrong. If the temperature is constant, pressure will have little effect on the movement and energy of molecule.

hurricanes form when warm, moist air from the ocean surface quickly rises into the atmosphere and forms storm clouds and rain. when the clouds are formed, heat is released which warms the cool air in the upper regions of the atmosphere so that the cycle can continue. which two phases of the water cycle are repeated in this process?

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.