Question
Will decreasing the pressure increase, decrease or have no effect on the number of collisions between the particles of two reacting gases? increase no effect decrease
Answer
4.5
(258 Votes)
Katie
Professional · Tutor for 6 years
Answer
decrease
Explanation
The concept of reacting gases forming a reaction in presence of a pressure difference often relates to the Collision Theory. According to the Collision Theory, for a reaction to occur, it is not sufficient for particles to just come into contact with each other. They have to collide with a certain minimum kinetic energy, also known as the activation energy, for the reaction to occur. If the pressure is decreased, the gas particles have a larger volume to spread out into (because pressure and volume are inversely related in gases according to Boyle's Law). Consequently, there's less frequency of effective collisions (collisions with energy greater than or equal to the activation energy) taking place, as particles have to travel greater distances to collide with each other. Hence, decrease in pressure decreases the number of effective collisions, thus slowing down the rate of reaction.