2 2. The energy stored in a substance that can be released when the substance reacts. A. Mechanical Energy B. Thermal Energy C. Chemical Energy D. Potential Energy

C. Chemical Energy

Explanation:

The energy that stored in the substance or in compounds is called chemical energy which released when the substance reacts.

A substance is made up of atoms and molecules and chemical energy is present in those atoms or molecules. When a chemical reaction takes place, these energy released from atoms and molecules.

Chemical energy can be released in the form of  thermal energy (heat) and mechanical energy (working ability).

Hence, the correct answer is "C. Chemical Energy".

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

answerambulatory;