lesson
Updated 6 days ago · 1 view
A sealed bottle of hydrogen peroxide (H2O2) can sit in your medicine cabinet for months without breaking down. But drop in a tiny pinch of manganese(IV) oxide powder, and it immediately erupts into roaring oxygen gas and steam.
What happened to that black powder during the reaction?
What Is a Catalyst?
A catalyst is a substance that increases the rate of a chemical reaction without being used up or chemically altered in the process. In 1835, Swedish chemist Jöns Jacob Berzelius observed substances facilitating chemical changes without being consumed and coined the term catalysis.
📊Interactive diagram
Because a catalyst is never consumed, its mass remains constant from the start of the reaction to the end. A small amount of catalyst can repeatedly process millions of reactant molecules without losing effectiveness.
If a catalyst is neither a reactant nor a product, how do we write it in a chemical equation?
Catalysts in Chemical Equations
In a balanced chemical equation, reactants are written on the left and products on the right. Because a catalyst is neither consumed nor created as a net product, we write its formula above the reaction arrow.
📊Interactive diagram
Common Misconception
A common mistake is thinking that catalysts 'never take part' in a reaction. In reality, a catalyst actively bonds with reactants during intermediate steps, but it is always regenerated in its original chemical state by the final step.