At a recycling plant, old tin cans are melted down and reconstructed. this is an example of a

Physical change

Explanation:

Different types of changes take place. Two such changes are physical change and chemical change.

Physical change

This takes place when a substance changes from one state to another without changing the chemical composition. For example, water changes from liquid to solid (ice) when frozen. Thus, water has not changed its chemical properties. A physical change is reversible.

Thus, the melting of aluminium cans is a physical change.

Chemical change

This is a reaction that changes the original reactants to give different products. For example, burning coal gives ash, soot, carbon dioxide and water. Most chemical reactions are irreversible.

a 20-cm-long, cylindrical graphite (pure carbon) rod is inserted into an oxidizing atmosphere at 1145 k and 1.013 x 105 pa pressure. the oxidizing process is limited by the diffu- sion of oxygen counterflow to the carbon monoxide that is formed on the cylindrical surface.