If an asteroid the mass of the on the one that possibly caused the extinction of the dinosaurs struck the moon would the material expelled from the crater possibly reach earth and would it create massive meteorite impacts.
The asteroid which may have wiped out the dinosaurs was probably somewhere between 2 and 10km in size. An asteroid that large striking the Moon would release a large amount of energy and it probably would eject some of the moon rock into space, however I would guess that the bits would be quite small, so if they happened to be going in the right direction to hit the Earth they wouldn't cause too much damage. Around 15 meteorites found on Earth have been identified as originating on the Moon, so it obviously is possible for ejecta from the Moon to reach the Earth, however this is a tiny amount relative to the total number of meteorites found on the Earth.
A nice internet site which discusses meteorites in more detail is the Nine Planets Meteorite page.
This page was last updated on July 18, 2015.