Question

question 20 which of the following has one example of a physical change and one example of a chemical change? dissolving powder and shredding paper boiling water and melting wax rusting iron and baking a cake freezing water and burning coal

Explanation:

Physical changes do not change the chemical composition of a substance, like boiling water (liquid - to - gas state change) and melting wax (solid - to - liquid state change). Chemical changes result in new substances being formed, such as rusting iron (iron reacts with oxygen to form iron oxide) and baking a cake (chemical reactions occur between ingredients). Freezing water is a physical change (liquid - to - solid state change) and burning coal is a chemical change (coal reacts with oxygen to produce carbon dioxide and other substances). Dissolving powder is a physical change (the powder disperses in a solvent) and shredding paper is a physical change (changes the physical form of paper).

Answer:

C. boiling water and melting wax, rusting iron and baking a cake