Which of the following correctly describes a compound?

• A. A solution formed by dissolving a solute in a solvent.
• B. A mixture of two or more substances that can be separated by physical means.
• C. A pure substance consisting of only one type of atom.
• D. A substance composed of two or more elements chemically bonded in fixed proportions.

Answer: (D)

Verified step by step guidance

1. Understand the definition of a compound: A compound is a pure substance formed when two or more different elements are chemically bonded together in fixed proportions.
2. Analyze each option by comparing it to the definition of a compound:
3. Option 1 describes a solution, which is a homogeneous mixture, not a compound.
4. Option 2 describes a mixture, which can be separated physically and does not involve chemical bonding.
5. Option 3 describes an element, which consists of only one type of atom, not a compound.
6. Option 4 correctly describes a compound because it emphasizes chemical bonding and fixed proportions of elements.