Do chemical properties change when water boils?

No, because chemical properties are things that, by definition, remain the same even when matter experiences physical changes.

Water undergoes a phase change when it boils, which is a physical change because the substance is still essentially water; the molecules are just arranged differently. During a phase change, the intermolecular forces holding molecules together break apart and the molecules separate.

Chemical changes are defined as those that genuinely alter a molecule's composition; for example, adding oxygen bonds or dissolving the water molecule itself. Chemical reactions are necessary for these kinds of changes to occur rather than just phase changes.

No, boiling water does not change the chemical makeup of water; boiling water only causes a temperature increase that changes the physical state of water from liquid to gas (water vapor).