9701 · 8.1
Rate of reaction
Reaction rate is simply how fast reactants are converted into products. This speed is governed by how often and how energetically particles collide with each other.
Need to know
What you need to know
- **Energy Condition:** The colliding particles must have a combined kinetic energy that is equal to or greater than a minimum value called the activation energy ($E_a$). This energy is needed to break existing bonds and initiate the reaction.
- **Orientation Condition:** The particles must collide in the correct spatial orientation, allowing the relevant atoms to come into contact and form new bonds.
Explanation
The Speed of Chemistry
- Rate depends on the frequency of collisions between particles and the energy they possess when they collide.
- The limiting reagent is the reactant that gets completely used up first, determining the maximum amount of product that can be formed.
- Factors like surface area, concentration, temperature, and the presence of a catalyst can all be adjusted to change the rate of reaction.
- We can measure reaction rates by tracking a noticeable change over time, such as the loss of mass, the volume of gas produced, or a change in colour.