Concept:A catalyst speeds up a reaction by providing a different, lower-energy pathway, not by remaining unchanged in mechanism details.
Explanation:A catalyst increases the rate of a reaction by lowering the activation energy.
Biological catalysts are indeed called enzymes.
Catalysts are not consumed, so they do not appear in the overall balanced equation.
However, catalysts do alter the reaction mechanism by offering an alternative pathway.
They can also appear in the rate law even though they are regenerated.
Therefore, the statement that catalysts do not alter the mechanism and never appear in the rate law is false.
Answer:D. catalysts do not alter the mechanism of the reaction and never appear in the rate law