Which substance can affect the rate of a chemical reaction without itself being changed or used up during the reaction?

Answer 1

The answer you're looking for is a "catalyst". Unless you are in Chemistry 12, you don't need to know that reaction equations with more than 3 molecules on the reactants' side consist of several steps, in which intermediates (things that are produced/used and involved in the reaction, but are reused or produced before the end) like catalysts come into the reaction. Catalysts influence reaction rate, but do not show up in the final equation of an overall reaction. They are sometimes listed over the "arrow" in the equation. Inhibitors slow reactions, and are the opposite of catalysts in that way.

Source - Chem 12 Student under Jim Nattrass

Answer 2

A catalyst is a material that promotes a chemical reaction by its mere presence. It isn't changed or consumed in the process.

Wikipedia has more information, and a link is provided.

Answer 3

A catalyst can help a reaction occur without being either a reactant or product. Many catalysts work by providing a surface that the reactants and attach to and achieve a lower activation energy than when in the bulk. My favorite description was that a catalyst is like a single's bar for reactants - it helps them get together.

Answer 4

The generic term is "catalyst". One specific type of catalysts in biological systems are called "enzymes".

Answer 5

This substance is called catalyst.

Answer 6

catalysts

Answer 7

catalyst

Answer 8

an enzyme