In the context of classification of matter, a cup of black coffee (filtered, no cream or sugar) is best classified as which type of matter?

• A. Heterogeneous mixture
• B. Pure compound
• C. Pure element
• D. Homogeneous mixture (solution)

Answer: (D)

Verified step by step guidance

1. Recall the main categories for classifying matter: pure elements, pure compounds, homogeneous mixtures, and heterogeneous mixtures.
2. Understand that a pure element consists of only one type of atom, such as oxygen (O\_2) or gold (Au), so black coffee cannot be a pure element because it contains multiple substances.
3. Recognize that a pure compound is a substance made of two or more elements chemically combined in a fixed ratio, like water (H\_2O) or sodium chloride (NaCl). Black coffee is not a pure compound because it contains many different molecules and ions dissolved together.
4. Distinguish between homogeneous and heterogeneous mixtures: a homogeneous mixture has a uniform composition throughout, while a heterogeneous mixture has visibly different parts or phases.
5. Since black coffee (filtered, no cream or sugar) is a uniform liquid solution where the solutes (like caffeine and other compounds) are evenly distributed in water, it is best classified as a homogeneous mixture (solution).