In Figure 1 below, both powders fall into the same category - which one?  Compound, element, mixture, or solution?  ??? Element

Figure 1

In Figure 2 below, the gray / yellow powder is now considered to belong to a new category.  Which one?  (Use the same choices as the previous question) ??? Mixture

Figure 2

If there were the same number of atoms of each, what percent would each occupy? ??? 50% iron and 50% sulfur.

How could you separate the iron powder from the sulfur powder? ??? Using a magnet.

Are the sulfur atoms and iron atoms connected to each other in any way? ??? No

Do they each retain the same properties they had when they were separate? ??? Yes

Could you add more iron to this powder so that there was 60% iron and only 40% sulfur? ??? Yes - it is possible to add or take away atoms to change the percent.

Once the powder ignites, a chemical reaction is happening.  What is the name of the type of reaction shown in Figures 3 and 4?  ??? Combustion

Figures 3 and 4

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.  The conclusion states that "the solid formed is obviously a new substance because it does not have many of the properties that the original powders had."

 
Figures 5 & 6

Observe Figure 2 and Figure 5.  What are some of the properties which have changed?

??? Color turned to black ??? Powder is now consolidated

Other comments about changes:

• There is also a change in the mass - since some of the sulfur atoms were carried off as sulfur dioxide gas, the mass of the iron sulfide block in Figure 5 is slightly less than the mass of the original mixture in Figure 2.
• The magnetic properties of the iron, however, are still present.  This solid can be picked up using a magnet.

This chemical reaction has produced a new category of substance.  What is the new black solid?  Compound, element, mixture, or solution?  ??? Compound.

Could you separate the iron from the sulfur by using a magnet? ??? No. Why or why not? ??? Because the atoms are now bonded together.

Based on the fact that the chemical formula for this new substance is FeS, what is the percentage of each type of atom in the black solid? ??? 50% iron and 50% sulfur

Could you add more iron to this black solid so that there was 60% iron and only 40% sulfur? ??? No.   Why or why not? ??? Each atom of Fe is bonded to one S atom.