Crude copper has many metal impurities (for example, lead, zinc, nickel, and others) and does not conduct electricity well, so ultrapure copper is needed. Explain how an electrochemical cell is used to purify copper. You may include a diagram of the electrochemical cell in your explanation.

it is b that is the answer.

answer carbon and three oxygen atoms;

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.