Chem 1.2 Factors affecting reaction rate

What does collision theory state?

For a reaction to occur, particples must collide with the correct orientation and sufficient energy for a reaction to occur.

How do different factors affect reaction rate

They affect the frequency of particle collisions and/or the proportion of collisions that have enough energy to react

Two requirments for a collision to occur according to collision theory

• Correct geometry/orientation

• Sufficient energy

What happens if you increase the concentration of reactants? (3 points)

• Increasing the concetration of reactants in a solution increase reaction rate

• This is because there are a greater number of particles available to react

• This increases the frequency of collisions between particles

What happens if you decrease the concentration of reactants?

• Decreasing the concentration of reactants decreases the reaction rate.

• This is because there are fewer particles available to react

• This decreases the frequency of collisions between particles.

What happens if you increase the temperature of a reaction?

• Increasing the temperature increases the kinetic energy of the particles

• This increases the frequency of particle collisions, where a great proportion of collisions now have the energy needed to react

• The reaction rate goes up

What happens if you decrease the temperature of a reaction

• Decreasing the temeperature decreases the kinetic energy of the particle

• This decreases the frequency of particle collisions, and a smaller proportion of collisions will have the needed energy to react

• Reaction rate goes down

What happens when you increase the surface area of reactants

• Increasing the surface area of solid reactant increases the number of particles that are exposed and available to react

• This increase the frequency of particle collisions

• This increases the reaction rate

What happens when you decrease the surface area of reactants

• Decreasing the surface area of the reactants decreases the number of particles that are exposed and available to react

• This decreases the frequency of particle collisions

• This decreases reaction rate

What happens whn you increase the pressure of a reaction

• Increasing the pressure of a reaction involving gases forces the gas particles close together

• This increases the frequency of particle collisions

• The reaction rate has been increased

What happens when you decrease the pressure of a reaction

• Decreasing the pressure means that gas particles are further apart from one another, as there is more volume

• This will decrease the frequency of particle collisions

• Reaction rate has been decreased