Chapter 5- Kinetics Flashcards
What is the activation energy?
The minimum energy that particles must collide with for a reaction to occur
What must particles do in order to react?
Collide with sufficient energy and in the correct orientation
What is the rate of a reaction?
The amount of product produced or reactant used per unit time
What factors affect the rate of reaction?
Temperature, concentration, pressure/volume, catalyst
How does increasing temperature affect the rate of reaction?
Average kinetic energy of particles increases so many more particles have energy greater than or equal to activation energy.
Frequency of successful collisions increases greatly.
How does increasing concentration affect the rate of reaction?
More reactant particles in a given volume so they are closer so frequency of successful collisions increases.
How does increasing pressure/ decreasing volume affect the rate of reaction?
Increases rate of reaction. More reactant particles in a given volume sothey are closer so frequency of successful collisions increases.
How does increasing surface area affect the rate of reaction?
Increases the area for the reaction to occur on so frequency of successful collisions increases.
What is a catalyst?
A substance that increases the rate of a reaction without being used up in the reaction.
How does a catalyst affect the rate of reaction?
Increases rate of reaction. Provides an alternative reaction pathway with a lower activation energy.
More reactant particles have energy greater than or equal to activation energy so frequency of successful collisions increases.
What is the Maxwell-Boltzmann distribution and what does the area under the curve represent?
The distribution of energies of particles.
The total number of molecules in the sample so it must remain constant.
What are some key features of Maxwell-Boltzmann distribution?
Starts at origin as no particles have no energy.
Peak is at most probable energy.
Average kinetic energy is to the right of most probable.
The line must not touch the x axis
How does increasing temperature affect the Maxwell-Boltzmann distribution?
Curve shifts to the right as a much greater proportion of molecules have energy equal to or greater than the activation energy.
Peak of curve is lower (as area must remain the same).
How does a catalyst affect the Maxwell-Boltzmann distribution?
Curve is unchanged however the activation energy shifts to the left as it is lowered by catalyst. Greater proportion of particles have sufficient energy to react.
