How to determine the compounds having dipole moment from their structure?

dipole moment is a vector quantity.Dipole momentcan be defined as the product of magnitude of charges and the distance of separation between the charges.it is base on electronegativity of the atom.the atom having more electronegativity than less electronegative atom has direction of dipole moment towards more electronegative atom.
for ex

In the CH3Cl molecule, chlorine is more electronegative than carbon, thus attracting the electrons in the C—Cl bond toward itself (Figure 1).As a result, chlorine is slightly negative and carbon is slightly positive in C—Cl bond. Since one end of C-Cl is positive and the other end is negative, it is described as a polar bond. To indicate the increased in electron density, the dipole is represented by an arrow with a cross at one end. The cross end of the arrow represents the positive end and the point of the arrow represents the negative end of the dipole.



The vector will point from plus to minus charge and run parallel with the bond between 2 atoms. The symbol δ indicates the partial charge of an individual atom. In addition, the direction of vector implies the physical movement of electrons to an atom that has more electronegativity when 2 atoms are separated by a distance of r. In other words, the electrons will spend more time around atom that has larger electronegativity.
compound Dipole Moment (Debyes)
NaCl 9.0 (measured in the gasphase)
CH3Cl 1.87
H2O 1.85
NH3 1.47
CO2 0
CCl4 0