1. The problem asks to classify the rusting of metal and the formation of black ice as chemical or physical changes. 2. Definitions: - A chemical change results in the formation of new substances with different properties. - A physical change affects the form or appearance but does not create new substances. 3. Rusting of metal: - Rusting involves the metal reacting with oxygen to form iron oxide, a new substance. - Therefore, rusting is a chemical change. 4. Formation of black ice: - Black ice is frozen water, a change of state from liquid to solid. - No new substance is formed, so it is a physical change. Final answers: - Rusting of metal is a chemical change. - Formation of black ice is a physical change.