Final answer:
A firecracker explosion results in a chemical change due to the transformation of substances and production of new chemicals with different properties, but it also involves a secondary physical change due to the alteration of the material's physical form.
Step-by-step explanation:
When a firecracker explodes, giving off light and heat, and breaking the wrapper into many pieces, a chemical change takes place. This is because during the explosion, the substances within the firecracker react with oxygen, transforming the chemicals into new substances like carbon dioxide, water vapor, and others, which have different chemical properties from the original substances.
This process is known as a chemical reaction and is characterized by the production of heat and light, among other signs. Additionally, a physical change also occurs due to the alteration in the physical appearance of the firecracker materials, like the breaking up of the wrapper, although this aspect is secondary to the predominant chemical change.