Answer and Explanation:
Heating the magnesium metal is a physical change because after the process, the magnesium metal is still magnesium metal and no other substance is formed. When we heat the metal, we tranfer energy and the temperature is raised. It could include the melting of the metal, which is a change in the state of matter, but it is still a physical change because no chemical reactions occur.
Burning the magnesium metal is a chemical change because it involves the reaction with O₂ to form a different compound (a magnesium oxide).