AQA GCSE FOUNDATION Chemistry: Factors Affecting Reaction Rate

Factors Affecting Reaction Rate: AQA GCSE Foundation Chemistry

This tutorial explores the key factors that influence how quickly a chemical reaction proceeds. We will focus on the impact of temperature, concentration, and surface area.

1. Temperature

What happens?

• Increasing temperature speeds up the reaction.

Why?

• Increased kinetic energy: Higher temperatures mean particles move faster and collide more frequently with greater energy. This leads to more successful collisions, meaning more particles will have enough energy to overcome the activation energy barrier and react.

Example: Food spoils faster at higher temperatures because the chemical reactions involved in spoiling occur more rapidly.

2. Concentration

What happens?

• Increasing the concentration of reactants speeds up the reaction.

Why?

• More frequent collisions: Higher concentrations mean more reactant particles are present in a given volume. This increases the chance of collisions between reacting particles, leading to a faster rate of reaction.

Example: Burning a piece of wood in pure oxygen (high concentration) will result in a much faster and more vigorous combustion compared to burning it in air (lower concentration of oxygen).

3. Surface Area

What happens?

• Increasing the surface area of a solid reactant speeds up the reaction.

Why?

• More contact points: A larger surface area provides more points of contact between the reactant and its surroundings. This allows for more collisions between particles, leading to a faster reaction.

Example: A lump of sugar will dissolve slower in water than granulated sugar because the granulated sugar has a larger surface area exposed to the water, allowing more sugar molecules to come in contact with the water and dissolve.

Summary

In summary, the following factors influence the rate of a chemical reaction:

• Temperature: Higher temperature means faster reaction rate.
• Concentration: Higher concentration of reactants means faster reaction rate.
• Surface Area: Larger surface area of solid reactants means faster reaction rate.

Understanding these factors allows us to control the rate of chemical reactions in various applications, such as industrial processes and everyday life.