Which laboratory activities involve chemical changes?

its called a lab man

The green growing on the penny of copper and the rust forming on the nail of iron are chemical changes.

Boiling away salt water, scraping iron filings from a mixture of sand with a magnet, and breaking a rock with a hammer, are physical changes.

Extracting iron filings from a mixture of sand with a magnet is absolutely no change. That's merely separating items that got mixed up.