Final answer:
Thermal energy increases reaction rates by raising the temperature, which heightens the average kinetic energy of reactant particles leading to more frequent and energetic collisions. These more frequent and forceful collisions are more likely to overcome the activation energy barrier, effectively speeding up the rate of the chemical reaction.
Step-by-step explanation:
Thermal energy causes an increase in the reaction rate because it raises the temperature at which a chemical reaction occurs, leading to a number of effects on the reactant particles. Firstly, when reactant particles are heated, their average kinetic energy increases, which corresponds with a higher velocity of these particles. This change results in reactant particles colliding more frequently and with greater force, thereby increasing the number of collisions that have enough energy to surmount the activation energy barrier required for the reaction to proceed.
The main consequence of increased temperature is not just the greater frequency of collisions but also the higher proportion of those collisions that are adequately energetic, leading to an effective reaction. According to Collision Theory, this is why raising the temperature usually results in a higher rate of reaction. A widely accepted rule in chemistry suggests that a 10 °C increase in temperature can double the rate of a chemical reaction, demonstrating the significant impact that temperature has on the speed at which chemical reactions occur.