Which of the following terms are used to identify pure substances in chemistry?

• A. Homogeneous and heterogeneous
• B. Mixture and solution
• C. Solvent and solute
• D. Element and compound

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the definition of a pure substance in chemistry. A pure substance has a fixed composition and distinct properties, and it cannot be separated into other substances by physical means.
2. Step 2: Recognize that pure substances are classified as either elements or compounds. Elements consist of only one type of atom, while compounds consist of two or more elements chemically combined in a fixed ratio.
3. Step 3: Review the other terms given: 'homogeneous and heterogeneous' describe types of mixtures based on uniformity; 'mixture and solution' refer to combinations of substances that can be separated physically; 'solvent and solute' describe components of a solution, not pure substances.
4. Step 4: Conclude that the terms 'element and compound' correctly identify pure substances because they represent substances with fixed compositions and unique chemical identities.
5. Step 5: Summarize that identifying pure substances involves recognizing that they are either elements or compounds, distinct from mixtures or solutions.