8.1-8.3: Rate of Reactions, (Factors), graphs

Explosive combustion

Explosive combustion

________ occurs when there are many fine particles in the air.

catalyst

When a(n) ________ is used, the rate of reaction will increase.

Particles

________ need to have sufficient energy to react when they collide.

surface area

Increasing the ________ of a solid increases the collision rate.

rate of reaction

There are three things that can effect the ________.

explosive mixture

Methane gas mixed with air in coal mines can also form a(n) ________.

temperature

Increasing the ________ increases the rate of reaction.

Catalysts

________ (including enzymes) create alternative reaction pathways which have a lower activation energy.

How do physical changes differ from chemical changes?

A physical change affects the forces between particles. The particles and their chemical properties remain the same. A chemical affects the chemical properties of the substance.

What does the term ‘activation energy’ mean?

The minimum amount of energy required for a reaction to occur.

What must happen for a reaction to occur?

Particles must collide at the correct orientation with sufficient energy to react

How can the rate of a reaction be increased?

Increase the temperature.

• Increase the concentration.

• Increase surface area to volume ratio. - Add a catalyst.

• Increase the pressure (for gases).

How does surface area affect the rate of reaction?

Increasing the surface area of reactants increases the rate of reaction because there are more exposed particles so more frequent successful collisions.

What is an enzyme?

A biological catalyst that increases the rate of reactions in living cells without being used up.

How can rate of reaction be calculated?

Rate of reaction = Amount of reactant used or product formed/ Time (s)

Suggest units could be used for rate of reaction?

g/s and cm3/s and mol/s