What evidence indicates that a chemical change took place when the iron and sulfr combined to form iron sulfide?

Answer 1

When iron and sulfur combine to form iron sulfide, evidence of a chemical change includes the formation of a new substance with different properties than the reactants. This is indicated by the change in color, as the mixture transforms from the metallic gray of iron and the yellow of sulfur to the dark color of iron sulfide. Additionally, heat may be released during the reaction, and the new compound cannot be separated into its original elements by physical means, further confirming that a chemical change has occurred.