Question

classify each example as a physical change or a chemical change.
physical change chemical change
crushing an aluminum can
recycling used aluminum cans to make new aluminum cans
aluminum combining with oxygen to form aluminum oxide
water boiling

Explanation:

Physical changes do not change the chemical composition of a substance, while chemical changes result in the formation of new substances with different chemical properties. Crushing an aluminum can only changes its shape, not its chemical makeup. Recycling used aluminum cans to make new ones involves melting and reshaping, which is a physical - change process. Water boiling changes water from liquid to gas without altering its chemical formula (H₂O). Aluminum combining with oxygen to form aluminum oxide is a chemical reaction as a new substance (aluminum oxide) is formed.

Answer:

Crushing an aluminum can: Physical change
Recycling used aluminum cans to make new aluminum cans: Physical change
Aluminum combining with oxygen to form aluminum oxide: Chemical change
Water boiling: Physical change