Chemical Reactions & Rates

Define rate of reaction

The rate of reaction is tht speed at which a chemical reaction occurs.

How is reaction speed measured?

By how fast reactants are consumed or products are formed over time.

What are the factors that affect rate?

Concentration

Temperature

Surface area

Catalysts

What are the factors that do NOT affect rate?

Molecular weight of products

Total pressure of an inert gas

Amount of product formed

Shape or volume of container

How does changing particle size affect rates?

By altering the surface area of a solid reactant. Breaking a solid into smaller pieces exposes more internal particles, providing a larger surface area for other reactants to collide with, speeding up the reaction.

Link changing particle size to collision theory

The greater exposure leads to a higher frequency of successful collisions per second, increasing the reaction rate.

What must happen for a successful collision?

The colliding particles must have enough kinetic energy to equal or exceed the activation energy. They also need to collide facing the correct direction, meaning they need to align precisely.

Link energy & orientation to reactions

Most fundamental criteria to dictate if a collision will result in a reaction. Energy acts as a barrier that prevents molecules from reacting immediately. Molevules must hit each other in the correct spatial orientation.