Question

Why is food digestion a chemical change?

Answer 1

Because the chemical structure of the original materials is changing.

Explanation:

The digestion processes involve changing the composition of materials (food) by chemical interactions – changes in bonding, oxidation states and structure – of the materials with other chemicals (enzymes, acids) in our digestive tracts.

For comparison, a purely “physical change” does not change the composition of a material. So, water freezing to ice or boiling to steam is a physical change, not a chemical one. But reacting water with sodium to produce hydrogen and sodium hydroxide (different compounds from the original materials) is a chemical change.