Which of the following demonstrates a chemical change?

iron (Fe) reacting to water ((H2O)) and oxygen (o) to form iron oxide (Fe2O3)

steam condensing on a mirror

sugar and water mixing to create sugar water

dry ice vaporizing

1 answer

The scenario that demonstrates a chemical change is:

Iron (Fe) reacting to water (H2O) and oxygen (O) to form iron oxide (Fe2O3).

In this reaction, the iron undergoes a chemical change as it reacts with water and oxygen to form a new substance (iron oxide).

The other options involve physical changes:

  • Steam condensing on a mirror is a physical change as it involves a phase change from gas to liquid.
  • Sugar and water mixing to create sugar water is a physical change, because the sugar dissolves in water but does not change its chemical structure.
  • Dry ice vaporizing is also a physical change, as it involves a phase change from solid to gas.

Therefore, the only option that involves a chemical change is the formation of iron oxide.