Question

 If the intermolecular forces between molecules of a substance were very small, what effect would you expect this to have on the boiling point and vapor pressure of the substance? What properties would you look for in a molecule in order to have a low boiling point and high vapor pressure? Should the atoms of the molecules be large or small? Why might this matter? Give two or three examples of molecules where you might expect the intermolecular forces to be very small. 

Answer 1

Stronger intermolecular forces between molecules will likely result in higher boiling points because it will take more energy to break up the intermolecular forces as the strength of these forces increase. I would look for a non polar covalent bond to have a low boiling point. The atoms would be small because the nuclei of atoms of non-metallic covalent bonds have a much greater attraction for its negatively charged electrons because of an increase in positively charged protons found as you move across the Periodic Table.