Explanation:
A property that does not bring any change in chemical composition of a substance are known as physical properties.
For example, shape, size, mass, volume, density, etc of a substance are all physical properties.
And, a property that changes chemical composition of a substance is known as chemical property.
For example, precipitation, reactivity, toxicity etc are chemical property.
Producing colored sparks in fireworks, and rusting in the presence of water and oxygen depicts chemical properties.
Thus, we can conclude that following uses of iron are due to its chemical properties.
- producing colored sparks in fireworks.
- rusting in the presence of water and oxygen.