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.

the correct answer is:

a. formation of precipitation

percent abundance for cu-63 can be shown as:

63 x + 65 (1-x) = 62.9296

65 - 62.9296 = 2 x

x = 1.035

thus, percent abundance for cu-63 is 1.035

percent abundance for cu-65 can be shown as:

63 x + 65 (1-x) = 64.9278

65 - 64.9278 = 2 x

x = 0.0361

thus, percent abundance for cu-63 is 0.0361

the mass spectrum of cu-63 showing the intense peak as, this isotope is found in nature more abundantly around 92.38 % in comparison to cu-65 which is found 62.58 % naturally