Answer
Exploding of nitroglycerin is a chemical change.
Work Step by Step
During physical changes, the substance changes its physical appearance, but not its chemical composition. This includes things like physical observations (color, texture) melting and boiling points, density, and state.
Chemical changes involve a transformation of one substance into a chemically different substance. This means that changes that involve other substances will tend to be chemical changes.
This question asks us to determine whether a change is physical or chemical. The specific change is explosion of nitroglycerin. An explosion means that the final product will be chemically different. This means that a chemical change is occurring.