Which of the following can be broken down chemically into simpler substances?

• A. A heterogeneous mixture
• B. An element
• C. A homogeneous mixture
• D. A compound

Answer: (D)

Verified step by step guidance

1. Understand the definitions of the terms: An element is a pure substance that cannot be broken down chemically into simpler substances. A compound is a pure substance composed of two or more elements chemically combined and can be broken down chemically into simpler substances (its constituent elements).
2. Recognize that mixtures (heterogeneous or homogeneous) are physical combinations of substances and can be separated by physical means, not chemical breakdown.
3. Identify that the question asks which can be broken down chemically, so mixtures are excluded because they are separated physically, and elements cannot be broken down chemically.
4. Conclude that the correct answer is a compound, as compounds can be chemically decomposed into simpler substances (elements).
5. Summarize: Only compounds can be broken down chemically into simpler substances, unlike elements or mixtures.