Answer to Question #140456 in Chemistry for Conor

Question

In one experiment, magnesium metal is melted. In a second experiment, magnesium metal is burned. Classify the change in each experiment as chemical or physical. Explain your reasoning.

Answer 1

In the first experiment, where the magnesium metal is melted, the change is physical. In the second experiment, where the magnesium metal is burned, the change is chemical.

During the physical change, the chemical formula and identity of the substance is not altered. When the magnesium metal is burned, a chemical reaction takes place and the magnesium oxide is formed:

2Mg + O₂ $\rightarrow$ 2MgO.