KEY2CHEM

Energy of Collisions  

In addition to colliding with the correct orientation, particles must also collide with sufficient energy to react. The energy barrier that colliding particles must exceed in order to react is called the activation energy. Particles with energy sufficient to overcome the activation energy barrier and with correct orientation to rearrange bonds from reactants to products.


Example 1.

 

Which statement about collision energy is true?

A. Colliding particles will react at any energy as long as they have the correct orientation.

B. Colliding particles must have high energy to surpass the activation energy barrier but can have any orientation.

C. Colliding particles must have high enough energy to surpass the activation energy barrier and must have the correct orientation.

 

 

 

 

 

Solution

 

C. Colliding particles must have high enough energy to surpass the activation energy barrier and must have the correct orientation.

The fraction of particles that will react must have sufficient collision energy and correct collision orientation.

 


Example 2.

Colliding particles must have enough energy to overcome the _______ energy barrier.

A. activation

B. activity

C. action

 

 

 

 

 

Solution

 

A. activation

Colliding particles must have enough energy to overcome the activation energy barrier.


Example 3.

 

In the diagram below, which point represents a collision with sufficient energy to convert reactants to products? The dashed line represents the activation energy barrier.

A. A

B. B

C. C

 

 

 

 

Solution

 

C. C

Point C represents a collision with sufficient energy to overcome the activation energy barrier (for the particles to achieve the activated state).