Final answer:
The statement 'a silver statue begins to tarnish' is an example of a chemical change, as it involves silver reacting with sulfur compounds to form a new substance, silver sulfide. So the correct answer is option A.
Step-by-step explanation:
The statement that describes an example of a chemical change is 'a silver statue begins to tarnish'. Tarnishing occurs when silver reacts with sulfur-containing substances in the air to form silver sulfide, which is a new substance with different properties than the original silver.
This process is a chemical reaction because it involves the creation of new chemical bonds and the transformation into a distinct chemical compound. Other options provided such as coating a building with paint, waxing a floor, or a metal melting represent physical changes.
A physical change might involve a change in the state or appearance of the material, but it does not involve making new chemical substances. For instance, when a metal turns to liquid at a certain temperature, it has undergone a state change (solid to liquid) but is still the same substance chemically.