How is a compound different from a mixture?

How is a compound different from a mixture?

• A. A compound is always a mixture of solids; a mixture is always a liquid.
• B. A compound is a pure substance made of two or more elements chemically bonded; a mixture is a combination of substances not chemically bonded.
• C. A compound can be separated by filtration; a mixture cannot.
• D. A compound is always homogeneous; a mixture is always heterogeneous.

Answer: (C)

The key idea is that bonding determines how you can separate substances. A compound is a pure substance made of two or more elements joined by chemical bonds, giving it a fixed composition. Because those elements are chemically bound, you can’t separate them with simple physical methods like filtration; you’d need a chemical change to break the bonds. Mixtures, on the other hand, are made of substances that are not chemically bound to each other, so their components can often be separated by physical methods—filtration can remove an undissolved solid from a liquid, evaporation or distillation can separate liquids with different boiling points, and so on. So, filtration is a practical tool for separating parts of a mixture, but it won’t break apart a compound into its elements. That difference in how they’re held together explains why mixtures are separable by physical methods while compounds require chemical changes to separate.

The key idea is that bonding determines how you can separate substances. A compound is a pure substance made of two or more elements joined by chemical bonds, giving it a fixed composition. Because those elements are chemically bound, you can’t separate them with simple physical methods like filtration; you’d need a chemical change to break the bonds.

Mixtures, on the other hand, are made of substances that are not chemically bound to each other, so their components can often be separated by physical methods—filtration can remove an undissolved solid from a liquid, evaporation or distillation can separate liquids with different boiling points, and so on.

So, filtration is a practical tool for separating parts of a mixture, but it won’t break apart a compound into its elements. That difference in how they’re held together explains why mixtures are separable by physical methods while compounds require chemical changes to separate.