A catalyst is a substance that:
Only a very small mass of catalyst is needed to increase the rate of a reaction. However, not all reactions have suitable catalysts.
Different substances catalyse different reactions. The table describes three common catalysts.
|Iron||The Haber process (making ammonia)|
|Vanadium(V) oxide||The contact process (a stage in making sulfuric acid)|
|Manganese dioxide||Decomposition of hydrogen peroxide (produces water and oxygen)|
Notice that these catalysts are transition metals or compounds of transition metals.
However, it does increase the frequency of successful collisions because a greater proportion of collisions has the activation energy or more.
An enzyme is a biological catalyst. Enzymes are important for controlling reactions in cells. They are also important in industry. The use of enzymes allows some industrial reactions to happen at lower temperatures and pressures than traditionally needed.