Which statement correctly describes electrochemical cells? A. Electrochemical cells involve only oxidation reactions.

B. Electrochemical cells involve only reduction reactions.

C. Electrochemical cells involve oxidation-reduction reactions.

D. Electrochemical cells do not involve oxidation-reduction reactions.​

C. Electrochemical cells involve oxidation-reduction reactions.

Explanation: Oxidation occurs at the anode, and reduction occurs at the cathode.

colorless gas, exhibiting a blue glow when placed in an electric field

b) solid

its a type of rock

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