Which statement best defines an ore?

• A. A substance that is always pure and free from impurities.
• B. A mineral that cannot be used for metal extraction.
• C. A compound that contains only nonmetals.
• D. A naturally occurring material from which a metal can be extracted profitably.

Answer: (D)

Verified step by step guidance

1. Understand the term 'ore' in the context of general chemistry and metallurgy. An ore is related to the extraction of metals from natural sources.
2. Recall that ores are naturally occurring minerals or rocks that contain sufficient amounts of a metal or metal compound to make extraction economically feasible.
3. Recognize that ores are not necessarily pure substances; they often contain impurities and other minerals.
4. Eliminate options that describe pure substances, nonmetals only, or minerals that cannot be used for metal extraction, as these do not fit the definition of an ore.
5. Conclude that the best definition of an ore is a naturally occurring material from which a metal can be extracted profitably.