Describe the factors that influence the rate of... - SS2 Chemistry Chemical Kinetics Question

Several factors influence the rate of chemical reactions:

a.    Concentration: The concentration of reactants affects the rate of reaction. An increase in reactant concentration leads to more frequent collisions between particles, resulting in a higher reaction rate. For example, in the reaction between hydrochloric acid (HCl) and sodium thiosulfate (Na2S2O3), increasing the concentration of HCl will result in a faster reaction rate.

b.    Temperature: Increasing the temperature generally increases the rate of reaction. Higher temperatures provide more energy to reactant particles, increasing their kinetic energy and collision frequency. As a result, more successful collisions occur, leading to a faster reaction rate. For instance, in the combustion of propane (C3H8), raising the temperature will accelerate the reaction.

c.     Surface area: The surface area of solid reactants influences the reaction rate. Finely divided or powdered substances provide more surface area for reactant particles to interact, leading to a higher reaction rate. This is because a larger surface area allows for more collisions to occur. An example is the reaction between solid calcium carbonate (CaCO3) and hydrochloric acid (HCl), where powdered CaCO3 will react faster than larger solid pieces.

d.    Catalysts: Catalysts are substances that increase the rate of reaction without being consumed in the process. They provide an alternative reaction pathway with lower activation energy, allowing reactants to undergo more successful collisions. For example, the enzyme amylase acts as a catalyst in the breakdown of starch into glucose during digestion.