How many yard are in a cubic yard?

None. There are no yards in a cubic yard, because a yard is a linear unit of distance, whereas a cubic yard is a spacial unit of volume. A cubic yard is the volume occupied by a cube that measures...

A square yard is a unit of area. A cubic yard is a unit of volume. The two units are therefore incompatible.

None. Cubic yards is a measure of volume & a yard is a measure of a linear distance.

There can be an infinite amount of square feet in one cubic yard, since square refers to the second dimension, and not the third, like cube does. However, there are 27 cubic feet in one cubic yard.

The answer cannot be known without knowing the substance you are talking about. Kilograms is weight, and cubic yards is volume. A cubic yard of gold is going to weigh more kilograms than a cubic yard...