1. A pure substance is a chemical substance that has the same composition throughout. There are two
types of pure substances: elements and compounds. Each pure substance has characteristics, or
properties, that can be used to identify it. Physical properties are traits that can be observed and tested
without a chemical change taking place. Some examples of physical properties are freezing point, color
and density. Metals are a group of pure substances. They are good conductors and have high boiling
points. Chemical properties describe how a substance will react during a chemical change. For example,
iron is a metal that will rust when combined with oxygen.
Which of the following does not describe a physical property of iron?
A. Iron is silvery-white or gray in color.
B. Iron has a boiling point of about 3,000°C.
C. Iron is a magnetic element.
D. Iron and sulfur react to form iron sulfide.