Which statement describes a catalyst?
catalysts appear as reactants in a chemical equation.
catalysts are completely consumed by the reaction.
catalysts provide a lower energy pathway for the reaction.
catalysts speed up chemical reactions by increasing surface area.

Option (c) is the correct answer.

Explanation:

A catalyst is a substance which increases the rate of a chemical reaction without itself getting consumed.

It is known that all catalysts are enzymes but all enzymes are not catalysts. Therefore like enzymes, a catalyst also lowers the activation energy of a reaction so that molecules with less amount of energy can easily participate in the chemical reaction.

Hence, the path of reaction changes and the rate of reaction increases.

Thus, we can conclude that catalysts provide a lower energy pathway for the reaction.

2fe + 3h2so4 -> fe2(so4)3 + 3h2

it is necessary to balance equations in order to get the proper amount of reactants as well as products in order not to make a miscalculation.

you cannot change the subscripts as that would change the substance itself. for instance, diatomic elements such as h2 only have the subscript two when a gas. another example would be so4, if you were to change the subscript, the element would no longer be sulfate.

we change the coefficients instead as that only changes the number of molecules rather than the substance itself.

hope this !