Laboratory Investigation:

Iron and Sulfur 

 

Introduction:

This experiment is a perfect introduction to chemical reactions.  It shows what happens when two atoms become bonded together to make a new molecule. 

 

Method:

  1. First, a little bit of each type of atom is collected.  On the left is a black powder.  It is composed of iron atoms.  The chemical symbol for iron is Fe.  On the right is a yellow powder made up of sulfur atoms.  The chemical symbol for sulfur is S.

    • iron_and_sulfur01.jpg (15176 bytes) Figure 1   
      (click to see a bigger picture)

  2. The two types of atoms are stirred together to form a gray / yellowish powder.  

    • iron_and_sulfur04.jpg (12304 bytes)   Figure 2 

  3. The powder is placed on a brick and put under a ventilated hood.  Then, using a Bunsen burner, the powder is ignited.   

    • iron_and_sulfur05.jpg (25440 bytes) Figure 3 

  4. After a few moments, the powder burns all by itself.

    • iron_and_sulfur02.jpg (18623 bytes) Figure 4 

 

 

Results:

At the end of the experiment, the powder has been transformed into a brittle, porous black solid.  It has the consistency of a burnt cookie.

  • iron_and_sulfur06.jpg (17319 bytes) iron_and_sulfur03.jpg (9536 bytes) Figures 5 & 6 

 

 

Conclusion:

The solid formed is obviously a new substance because it does not have many of the properties that the original powders had. During the burning of the powder, a chemical reaction happened (called combustion) which allowed the atoms to rearrange themselves.

One compound which is formed is sulfur dioxide, an invisible toxic gas.  It is for this reason that the experiment must be done under a ventilated hood.  The other compound is the newly formed black solid called iron sulfide.  Its chemical formula is FeS.

 

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