# Dipoles and determining molecular (a)symmetry [closed]

What is a dipole? Also, how do you know if a molecule is symmetrical or asymmetrical?

For example, are the following symmetrical or asymmetrical? Can you tell just from the molecular formula? Which ones have dipoles?

• $\ce{O2}$
• $\ce{H2O}$
• $\ce{CO2}$

Are these concepts related?