The snapping turtle is a large freshwater turtle of the family Chelydridae that ranges from southeastern Canada south, west to the Rocky Mountains. They have powerful beak-like jaws and highly mobile head and neck. On the other hand Sea turtles are found in all the world's oceans except the Arctic Ocean .There are seven living species of sea turtles and all have less power in jaws and head. They don't normally live outside the water for long.

 Differences:
1: Snapping turtles prefer fresh water, and mostly reside in the bays, where as sea turtles live in oceans.
2: Snapping turtles have webbed feet, which help them walk on the land, where as the sea turtles' limbs are modified in to flippers, which help them swim and travel long distances in the oceans. They don't need webbed feet because they just go to the nearby beaches for breeding. But the snapping turtles have to walk a lot on uneven land, so they have got webbed feet.
2: Snapping turtles have snake like morphology, thus named as "Chelydra Sarpentiatext"

Similarities:
1: Both have scales called as "scutes" on their bodies.
2: Both go to land for breeding and nesting.
3: Both are carnivores.