Explain why `H_(2)O` has dipolemoment while `CO_(2)` does not have.

Explanation

Dipolemoment of a polyatomic molecule is a vector quantity.
`H_(2)O` molecule has angular structure with two O-H bonds, oriented at an angle of `104.5^(@)`.

So the dipolemoment of the water molecule is the resultant of the dipolemoments of two O-H bonds.
The dipolemoment in the case of `CO_(2)` is zero. This is because the two equal bond dipoles point in opposite directions and cancel the effect on each other.