Complete the sentence.
In this chemical reaction, copper is a ().

 - reactant
 - product
Read the underlined text carefully. Look for information about what happens to copper in this chemical reaction.
When the Statue of Liberty in New York City was built in the late 1800 s, it was reddish-brown. Today, a green layer, called a patina, covers the statue's surface. This layer formed over time as copper in the statue combined with oxygen and other gases in the air to form the patina.
The underlined text tells you that when copper in the statue and oxygen combine, a patina is formed. When copper and oxygen react, or go through a chemical change, their atoms are rearranged to form the patina. Because copper reacts in this chemical reaction, copper is a reactant.