How do catalysts affect chemical reactions?

Catalysts play a crucial role in chemical reactions by lowering the activation energy required for the reaction to take place. This means that a catalyst enables reactions to occur at a faster rate or under milder conditions than would otherwise be necessary. By facilitating the rearrangement of molecules during a reaction, catalysts allow the reactants to convert into products more efficiently.

This property is vital in many applications, including industrial processes and catalytic converters in vehicles, where efficiency and reduction of harmful emissions are required. By making it easier for reactions to occur, catalysts can significantly affect the overall energy dynamics of a reaction, allowing for faster completion and better yields without being consumed in the process.

The other choices do not accurately describe the function of catalysts in reactions. Catalysts do not increase the temperature needed for reactions, they do not stop reactions from occurring, and they do not inherently increase byproducts. Their primary role is to enhance the reaction process by lowering the energy barrier, making them an essential component in chemistry.