Do chemical properties change when water boils?
No. Chemical properties, by definition, are things that do not change even when matter undergoes physical changes.
When water boils, the water turns from a liquid to a gas. During a phase change, the intermolecular forces that hold molecules together break apart and the molecules separate. This is a physical change, because the substance is still fundamentally water, the molecules are just arranged differently.
A chemical change is something that actually changes the composition of a molecule, like adding oxygen bonds or breaking apart the water molecule itself. This does not happen with a simple phase change, but requires a chemical reaction to take place.