C8 - Chemistry - Rates and Equilibrium

What is the equation for the mean rate of a reaction?

mean rate = amount of reactant used or product formed / time taken

What does a steeper gradient represent?

A steeper gradient represents a higher rate of reaction.

What does the collision theory state?

For a reaction to occur:

• The reactants must collide.

• The reactants must collide with enough energy for bonds to be broken.

How can the rate of reaction be increased?

You can increase the frequency of collisions and increase the kinetic energy of the particles when they collide.

What factors affect the rate of a reaction?

• Temperature.

• Surface Area.

• Pressure.

• Concentration.

• Presence of a catalyst.

How can conditions be altered inside a closed vessel?

Change the concentration of one of the substances, change the temperature of the entire reaction and change the pressure inside the vessel.

Describe what happens at dynamic equilibrium.

The amounts of reactant and product are constant but not necessarily equal. The ratios can be different, and it is the reaction conditions that determine this.

What is a reversible reaction?

One in which the products can react to produce the original reactants.

What does Le Chatelier’s principle state?

At equilibrium, the amount of products and reactants is constant. To change the ratio of reactants: products, the conditions of the reaction must be changed. The closed system will then counteract this change by favouring either the forward or the reverse reaction.