* Catalysts speed up reactions: They provide an alternative reaction pathway with a lower activation energy, making the reaction happen faster.
* They remain unchanged: Catalysts are not consumed in the reaction. They participate in the reaction mechanism but are regenerated in their original form at the end.
Think of it like this: Imagine a catalyst as a matchmaker. They bring reactants together so they can react faster, but the matchmaker themselves don't change in the process. They can go on to make more matches.
Example: In the decomposition of hydrogen peroxide (H₂O₂), manganese dioxide (MnO₂) acts as a catalyst. The reaction is:
2H₂O₂ → 2H₂O + O₂
The MnO₂ speeds up the reaction but is not consumed. It can be recovered after the reaction is complete.
Important Note: While catalysts are not used up in the reaction, they can be deactivated by various factors like poisoning (contaminants), changes in temperature or pressure, or even by the reaction products themselves.
