Q: Serial number and stolen Mac

The serial number is on the back. If you had enabled 'Find My Mac' before it was stolen then you can go to http://www.icloud.com and goto the 'Find My Phone' page, however the location will be calculated from nearby wifi networks and will be very approximate; also the Mac has to be on, not wiped, and able to connect to a network. If you had not enabled 'Find My Mac' then there is no way of locating it. All you can do is report it to the police.