Rates of reactions
The speed of a chemical reaction is affected by four factors: concentration, temperature, particle size, and the presence of a suitable catalyst. This video shows demonstrations that illustrate each of these factors.
Key learning points:
- Particles must collide for a chemical reaction to happen.
- The rate of a reaction depends on the frequency and energy of collisions between particles.
- Starch reacts with iodine to turn blue/black
- Increasing concentration increases reaction rate because the collisions are more frequent.
- Increasing temperature speeds up a reaction because there are more collisions and the collisions have higher energy.
- Catalysts speed up reactions by increasing the number of successful collisions.
- Catalysts are not used up in a reaction.
- Smaller particles have a larger surface area.
- Increasing surface area increases a rate of reaction.