Rate of reaction
Rate of reaction
- The rate of reaction is how fast reactants turn into products.
- For particles to react, they must collide.
- But not every collision works.
Practice
Rate of reaction is measured as the:
Rate is how much the concentration (or amount) changes in each unit of time.
Effective collisions
- An effective collision has enough energy and the correct direction — so a reaction happens.
- A non-effective collision lacks energy or hits at the wrong angle — nothing happens.
- The rate depends on the frequency of effective collisions per second.
Practice
An effective collision is one that:
A collision only reacts with sufficient energy and the right orientation.
Practice
The rate of reaction depends on the:
More effective collisions per second means a faster rate.
Concentration and pressure
- Increasing concentration (or gas pressure) packs particles closer together.
- They collide more often, so there are more effective collisions per second — the rate rises.
Practice
Increasing the concentration of a reactant speeds up the reaction because:
More particles in the same volume collide more frequently, raising the rate.
You've got it
Key idea
- rate = change in concentration (or amount) per unit time
- an effective collision needs enough energy + correct orientation
- rate depends on the frequency of effective collisions
- higher concentration/pressure → more frequent collisions → faster rate