Presentation on theme: "Factors Effecting Reaction Rate. Collision Theory In order to react molecules and atoms must touch each other. They must hit each other hard enough to."— Presentation transcript:
Factors Effecting Reaction Rate
Collision Theory In order to react molecules and atoms must touch each other. They must hit each other hard enough to react. Anything that increase these things will make the reaction faster.
Things that Effect Rate Temperature - Higher temperature faster particles. - More and harder collisions. - Faster Reactions. Concentration - More concentrated closer together the molecules. - Collide more often. - Faster reaction.
Things that Effect Rate Particle size - Molecules can only collide at the surface. - Smaller particles bigger surface area per volume. - Smaller particles faster reaction.
Orientation Colliding alone is not enough to guarantee reaction Relative orientations of the molecules may determine if the energy gets to the right place or if they are suitably oriented to form the new bonds As temp increases, the number of collisions increases as does the fraction that are oriented correctly
Activation Energy A certain amount of energy must be available to “propel” the molecules from one chemical state to another This energy barrier is called the Activation Energy (E a ) Arrangement of atoms that has this maximum energy is called the activated complex
Energy Reaction coordinate Reactants Products
Energy Reaction coordinate Reactants Products Activation Energy - Minimum energy to make the reaction happen
Energy Reaction coordinate Reactants Products Activated Complex or Transition State
Energy Reaction coordinate Reactants Products Overall energy change
Boltzmann Distribution In any sample of a substance, there exists a distribution of velocities of the particles Only some the particles have sufficient energy to reach the minimum activation energy
As the temperature increases, the number of molecules with minimum activation energy increases