## Dipole Moments Question

kristinstlew
Posts: 20
Joined: Fri Sep 25, 2015 3:00 am

### Dipole Moments Question

What are Dipole moments and how do you calculate them? I know that in class we have drawn vectors to represent the pull in electronegativity, but I am a little confused how this relates to chemical bonds and when we need to know the value of dipole moments.

KaylaH
Posts: 26
Joined: Fri Sep 25, 2015 3:00 am

### Re: Dipole Moments Question

A dipole moment is equal to the magnitude of charge times the distance.

If for example you took the molecule HCl, we know that they are connected by a single bond (with 3 lone pairs of electrons around Cl). Cl is more electronegative so it will pull the electrons toward it. We would draw an arrow toward Cl because it is gaining electron density and getting “more negative”. This creates a polar molecule. When you look at these two poles as having a center of mass, you can look at these poles having a distance between them and you could calculate the dipole moment for this molecule. The bond is polarized, and the molecule is polar, so thus it has a dipole moment.