Collision Theory and Chemical Reaction Rate

Collision Theory and Chemical Reaction Rate

by Mervin Selmo

​Objectives

1. Define Collision Theory ​and describe how it affects the chemical reaction

2. ​Explain the different factors affecting the rate of chemical reaction

Poll

A chemical change that occurs when two or more substances combine to form a new substance

• Product

• Chemical Kinetics

• Chemical Reaction

• Activation Energy

​Chemical reactions are common in our daily lives

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Chemical ​change vs. Physical Change

Identify the following statement whether the statement is a Chemical or Physical Change​

Poll

Baking a pie

• Chemical Change

• Physical Change

Poll

Burning a paper

• Chemical Change

• Physical Change

Poll

Melting ice

• Chemical Change

• Physical Change

Poll

Sugar dissolved in water

• Chemical Change

• Physical Change

Poll

Mixing paint to make new color

• Chemical Change

• Physical Change

​Chemical Change

​chemical reaction, occurs when atoms of a substance are rearranged, and the bonds between the atoms are broken or formed

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​ Change in Temperature

• Change in Color

• Noticeable Odor (after reaction has begun)

• Formation of a Precipitate

• Formation of Bubbles

Physical Change

is any change in a substance’s form that does not change its chemical makeup

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​ Texture

• Color

• Temperature

• Shape

• Change of State

Collision Theory​

All substances are comprised of millions of tiny particles in constant motion. These particles are colliding with each other constantly in any substance. All collisions between particles do not result in a reaction

​There are two factors that determine whether a reaction will occur between two particles that are colliding

• ​Substances or particles of reactants must physically collide with enough energy

• ​Substance or particles must come into contact or collide in the correct orientation (facing the correct way).

​Collision Theory

​The collision theory states that reacting substances must come into contact (collide) with enough activation energy, and in the correct orientation (facing the correct way), so that their electron shells can rearrange to form the products of the reaction

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​Therefore, any factor which changes the frequency or energy of the collisions will change the rate of the reaction.

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​What is a Chemical Reaction?

​When two particles collide, sometimes a chemical reaction can occur, which means the bonds between two or more particles are broken and reformed, creating one or more new substances. The substances or particles that enter and is changed in the chemical reaction are called reactants and the substances that are formed are called products.

​Factors affecting rate of chemical reaction