Activation energy and catalysts

Even when a reaction releases energy overall, reactant particles need a minimum amount of energy when they collide in order to react, called the activation energy. It is like a hill the reactants must climb before rolling down to the products; on an energy diagram, it is the height from the reactants up to the top of the curve. Only collisions with at least this much energy, and the right orientation, lead to products. Raising the temperature speeds up a reaction mainly because a larger share of collisions then have enough energy. A catalyst speeds up a reaction by providing a different pathway with a lower activation energy, without being used up itself, so a small amount can be used again and again. A catalyst does not change the reactants, the products, or the overall energy the reaction releases or absorbs. Examples include the catalytic converter in a car, which helps turn harmful exhaust gases into less harmful ones, and enzymes, the protein catalysts that speed up reactions in living things. Increasing surface area, such as grinding a solid into powder, also speeds up a reaction by exposing more particles to collisions.

This explanation is AI-generated and can occasionally be wrong. 🚩 Report