Which of the following is NOT a difference between a compound and a mixture?

• A. Compounds can be separated into their components by physical means, while mixtures require chemical means for separation.
• B. The properties of a compound are different from those of its constituent elements, while the properties of a mixture are similar to those of its components.
• C. Compounds have a fixed composition, while mixtures can have variable composition.
• D. Compounds are formed by chemical bonding between elements, while mixtures involve no chemical bonding.

Answer: (A)

Verified step by step guidance

1. Understand the definitions: A compound is a substance formed when two or more elements chemically bond together, resulting in a fixed composition and unique properties. A mixture is a physical combination of two or more substances where each retains its own properties and composition can vary.
2. Analyze the first statement: "Compounds can be separated into their components by physical means, while mixtures require chemical means for separation." Recall that compounds require chemical methods to break bonds and separate elements, whereas mixtures can be separated by physical methods like filtration or distillation. This statement is incorrect and thus NOT a true difference.
3. Review the second statement: "The properties of a compound are different from those of its constituent elements, while the properties of a mixture are similar to those of its components." This is true because compounds have new properties due to chemical bonding, while mixtures retain the properties of their components.
4. Examine the third statement: "Compounds have a fixed composition, while mixtures can have variable composition." This is a correct distinction since compounds have definite ratios of elements, but mixtures can vary in proportion.
5. Consider the fourth statement: "Compounds are formed by chemical bonding between elements, while mixtures involve no chemical bonding." This is also true and a fundamental difference between compounds and mixtures.