A metal melts at 450°c. is this property of the metal classified as chemical or physical? explain your choice

Chemical properties describe how things undergo chemical reactions, while physical properties describe how things behave when they're not undergoing reactions.

In the case of melting a metal, the melted metal continues to be the same material - just in a liquid rather than a solid form. As a result, melting (and all phase changes, for that matter) is a physical change and the ability of the metal to melt at 450 degrees is a physical property.