What was the difference between a velociraptor and a coelophysis?

They are two very different species of dinosaur that lived at different times and in different places. They were both small bipedal predators in a group called theropods, the clade that includes all carnivorous dinosaurs.
Coelophysis was one of the earliest known dinosaurs. It lived in the late Triassic period about 215 million years ago in what is now the southwestern United States. It stood about 3 feet tall and was nearly 10 feet long . Coelophysis had four digits on its hands whearas velociraptor, like most carnivorous dinosaurs, only had three. It belonged to the family Coelophysidae, which lasted from the late Triassic to the early Jurassic.

Velociraptor, contrary to its depiction in Jurassic Park, was actually smaller than Coelophysis, standing about 2 to 2.5 feet tall and getting to be 6 or 7 feet long. It lived in the late Cretaceous perioud between 75 and 71 million years ago in what is now Mongolia and northern China. It belonged to the family Dromaeosauridae, which lasted from the late Jurassic period until the end of the Cretaceous. One of velociraptor's notable features, one that it shared with other dromaeosaurids, was that its inner toe was elevated off the ground and bore a large claw which it likely used for killing or immobilizing prey. Overall , velociraptor was very birdlike and even bore large feathers on its arms. Although no direct evidence of feathers on coelophysis, it is not out of the question that id had them, though if it did, those feathers would not have been as well developed as those of velociraptor.