Atoms are rearranged in a chemical reaction. The substances that:
No atoms are created or destroyed in a chemical reaction. This means that the total mass of the reactants is the same as the total mass of the products. We say that mass is conserved in a chemical reaction.
The reaction between iron and sulfur is often used to study elements and compounds. Iron sulfide is the compound produced in the reaction. The slideshow shows what happens in this reaction:
Iron sulfide, the compound formed in the reaction, has different properties to the elements from what it is made. The table compares the properties of iron, sulfur and iron sulfide:
|Type of substance||Element||Element||Compound|
|Is it attracted to a magnet?||Yes||No||No|
|Reaction with hydrochloric acid||Hydrogen formed||No reaction||Hydrogen sulfide formed, which smells of rotten eggs|
The atoms in a compound are chemically joined together by strong forces called bonds. This is why the properties of a compound are different from the elements it contains, and why you can only separate its elements using another chemical reaction. Separation methods like filtration and distillation will not do this.