What term describes a carbon atom that has four different groups bonded to it?

A carbon which is attached to four different atoms or group of atoms with different environment is called as Chiral Carbon or Asymmetric Carbon.

Non-superimposable:
                                     The mirror image (molecule) of chiral carbon cotaining compounds are Non.Superimposable on each other. They are called enantiomers of each other.

Polarized Light and Chiral Carbon:
                                                       When a polarized light is allowed to fall on either enantiomer of chiral compound, it is rotated other clockwise or anti-clockwise.

Examples:
                Below are three axamples of compounds containing chiral carbon.

Answer is to avoid experimental error

Depends on the speed of the car.