CONDITIONS FOR EFFECTIVE COLLISIONS

This article is basically discussing the conditions for any chemical reaction to occur. There are basically two conditions for effective collisions. They include:

• ·         The reacting particle must be properly oriented during collision.
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• ·         The reacting molecules must collide with enough energy for bond to break (activation energy).

The orientation of collision:

For a collision to be effective, the collision must be properly oriented. Consider a simple reaction involving a collision between two molecules, ethane, CH2=CH2, and hydrogen chloride HCL, for example. This reacts to give chloroethane.

As a result of the collision between the two molecules, the double bond between the two carbons is converted into a single bond. A hydrogen atom gets attached to one of the carbons and a chlorine atom to the other.

  CH2=CH2 + HCL ---------- CH3CH2CL

The reaction can only happen if the hydrogen end of the H-CL bond approaches the carbon-carbon double bond. Any other collision between the molecules doesn’t work.

Note that any other collision will cause a repulsion in the reaction (i.e., they will bounce off).

Activation energy:

This is the minimum amount of energy needed for a reaction to take place. For every reaction to take place that reaction must overcome an energy barrier. Therefore for a reaction to be effective, it must possess enough activation energy.