My Galaxy 5 is lost somewhere in the house but is either on mute or dead anyway, how can I locate it?

Son was using my phone wife put it in"a safe place" now can't find. Tore house apart etc.

If you have a google account connected to your phone go to your computer and sign in to the google account.
Google has an Android Device Manager page (just google it) that will let you ring your phone for 5 minutes or can locate it via GPS if the battery is not dead.
Good Luck