A substance consisting of two or more elements chemically combined is called a

• A. Element
• B. Compound
• C. Mixture
• D. Solution

Answer: (B)

Two or more elements chemically bonded form a compound. In a compound, the elements join in a fixed ratio and the resulting substance has properties that are different from the elements on their own. This is different from a mixture, where substances are simply physically combined and can usually be separated by physical means, and from a solution, which is a homogeneous mixture where the components are dissolved but not chemically bonded to each other. To separate a compound into its elements, chemical changes that break the bonds are needed, not just physical separation. Water (H2O) and table salt (NaCl) are classic examples.