Which term describes a substance made of two or more elements joined in a fixed ratio?

Which term describes a substance made of two or more elements joined in a fixed ratio?

• A. Compound
• B. Element
• C. Mixture
• D. Pure Substance

Answer: (A)

When two or more elements join in a fixed ratio, a new substance is formed through chemical bonds and has a definite composition. This is a compound. The specific ratio means the elements are chemically combined in a way that doesn’t vary, and the resulting material often has properties different from the elements on their own—water is a classic example, with two hydrogens for every one oxygen, a ratio that stays constant. Because the elements are bonded, you can’t separate them by simple physical methods; you’d need a chemical reaction to break the bonds. This distinguishes a compound from an element, which is made of only one type of atom, and from a mixture, where components are physically combined and can vary in proportion while each component retains its own properties. A compound is also a pure substance, but it’s specifically a pure substance formed from two or more elements in a fixed ratio.

When two or more elements join in a fixed ratio, a new substance is formed through chemical bonds and has a definite composition. This is a compound. The specific ratio means the elements are chemically combined in a way that doesn’t vary, and the resulting material often has properties different from the elements on their own—water is a classic example, with two hydrogens for every one oxygen, a ratio that stays constant. Because the elements are bonded, you can’t separate them by simple physical methods; you’d need a chemical reaction to break the bonds.

This distinguishes a compound from an element, which is made of only one type of atom, and from a mixture, where components are physically combined and can vary in proportion while each component retains its own properties. A compound is also a pure substance, but it’s specifically a pure substance formed from two or more elements in a fixed ratio.