Question

when iron is burned, it combines with oxygen to form iron oxide. the table below shows the densities of all of these substances.

substance	iron	oxygen	iron oxide

based on the information from the data - table, which of these is a correct conclusion about the burning of iron?
a. a chemical reaction does not occur because both iron and iron oxide have high densities.
b. a chemical reaction does not occur because burning iron causes it to melt, which is a physical change.
c. a chemical reaction occurs because the density of iron is different from the density of iron oxide.
d. a chemical reaction occurs because each iron atom loses mass when it is burned.

Explanation:

A chemical reaction occurs when a new substance is formed with different properties. Density is a property. Since the density of iron is different from that of iron - oxide, a chemical reaction has occurred as a new substance (iron - oxide) with different density has been formed.

Answer:

C. A chemical reaction occurs because the density of iron is different from the density of iron oxide.