how do the following changes affect the speed of a reaction?
a)Increasing the concentration of the reactans.
b)Decreasing the temperature.
c)Decreasing the partickle size of a solid reactant.
Increasing the concentration of the reactants increases the rate (because there are more particles in a certain volume to collide). Decreasing the temperature decreases the rate (because the kinetic energy of the particles is decreased, thus fewer collisions take place). Decreasing the particle size(making the particles smaller) of a solid reactant increases the rate (because the surface area is increased).
a) Increasing the concentration of the reactants:
To understand how increasing the concentration affects the speed of a reaction, you need to consider the collision theory. According to this theory, the rate of a chemical reaction depends on the frequency of collisions between the reacting particles. When you increase the concentration of reactants, there are more particles in a given volume, which leads to an increased frequency of collisions. A higher collision frequency means there will be more successful collisions, or collisions with enough energy to form products. Consequently, increasing the concentration of reactants generally speeds up the reaction.
b) Decreasing the temperature:
Lowering the temperature generally slows down a reaction. The rate of a chemical reaction is determined by the kinetic energy of the reacting particles. At higher temperatures, the particles have more kinetic energy, resulting in faster and more frequent collisions, increasing the reaction rate. When you decrease the temperature, the particles have lower kinetic energy, and their motion slows down. As a result, the collision frequency decreases, reducing the rate of the reaction.
c) Decreasing the particle size of a solid reactant:
Reducing the particle size of a solid reactant increases its surface area. According to the collision theory, reactions occur at the interface (surface) between reactant particles. When you decrease the particle size, you create more surface area for the reaction to take place. This increased surface area leads to a higher frequency of collisions between the reactant particles and potentially accelerates the reaction. Therefore, decreasing the particle size of a solid reactant generally speeds up the reaction.