Question

which cannot be chemically broken down into simpler substances?
○ compound
○ element
○ solution
○ mixture

Explanation:

To determine which cannot be chemically broken down into simpler substances, we analyze each option:

• A compound is made of two or more elements chemically combined, so it can be broken down into its constituent elements (e.g., water, \(H_2O\), can be broken into \(H_2\) and \(O_2\) via electrolysis).
• An element is a pure substance made of only one type of atom. By definition, elements cannot be chemically broken down into simpler substances because they are already in their most basic form (e.g., gold, \(Au\), cannot be broken down into simpler substances chemically).
• A solution is a homogeneous mixture (e.g., salt water), and mixtures can be separated into components (e.g., by evaporation for salt water), so solutions can be "broken down" (separated) into their components.
• A mixture is a combination of two or more substances (elements or compounds) that are not chemically combined, so it can be separated into its components (e.g., a mixture of sand and salt can be separated by dissolving in water, filtering, and evaporating).

Answer:

B. element