Chemistry Unit 2

Front 1

What are collisions

Back 1

For a chemical reaction to occur, the reactant particles must collide. Collisions with too little energy do not produce a reaction. The collision must have enough energy for the particles to react. The minimum energy needed for particles to react is called the activation energy.

Front 2

If the concentration is increased, or the pressure is increased

Back 2

*There are more reactant particles in the same volume*There is a greater chance of the particles colliding*The rate of reaction increases

Front 3

If the particle size changed

(If a solid reactant is broken into small pieces or ground into a powder)

Back 3

*Its surface area is increased*More particles are exposed to the other reactant*There is a greater chance of the particles colliding*The rate of reaction increases

Front 4

Change of temperature

Back 4

*The reactant particles move more quickly*More particles have the activation energy or greater*The particles collide more often, and more of the collisions result in a reaction*The rate of reaction increases

Front 5

Catalysts

Back 5

Catalysts increase the rate of reaction without being used up. They do this by lowering the activation energy needed. With a catalyst, more collisions result in a reaction, so the rate of reaction increases. Different reactions need different catalysts.