Directions: the diagram shows a chemistry demonstration. use the diagram to answer any questions that follow. what happened to the substances in the test tube during step 2? group of answer choices the heat started a chemical reaction between the iron and sulfur resulting in the product iron sulfide. the heat started a chemical reaction in the compound iron sulfide. breaking it down to iron and sulfur. the heat started a physical reaction between the iron and sulfur resulting in the product iron sulfide the products iron and sulfur reacted making the reactant iron sulfide.