If you mix sulfur and iron filings together and you place them in a test tube then heat the test tube up, the mixed elements would begin to glow. After removing them from the heat, the test tube would cool down and you would be able to look at the result. Instead of yellow sulfur and iron filings, you would find a black glob of metal (shown on the right). If you held a magnet to it, the black glob would not be attracted to the magnet even though the iron filings were used to make it.

When elements are combined to make a new substance with its own properties, the resulting new substance is called a compound. This black glob is a new material called iron sulfide. Compounds do not have the properties of the elements that were used to make them. Iron sulfide is not like sulfur and it is not like iron; iron sulfide is a compound with its own unique properties.

In order to separate the iron from the sulfur and get back their original properties(the iron being magnetic and the sulfur yellow), you need another chemical reaction. You cannot just physically separate them.

Compounds are everywhere. Most of the matter that surrounds you is made up of compounds. Common compounds that you probably use every day are water (H + O), salt (Na + Cl), shown on the left, and sugar (C + H + O). Often a compound includes a metallic element combined with a non-metallic element.