Size vs Intermolecular Forces

[Warren Jolicoeur 1B]

How much does the size of the molecule affect its melting and boiling point. For example if i had a molecule that was very large (30 atoms) but only had Dispersion forces applied on it vs a HCl molecule, which would melt first?Thanks!

[Ryan Burchell 3D]

Size has a large effect on dispersion forces, the bigger a molecule is the stronger the dispersion forces are going to be. I can't be positive about your example but remember that dispersion forces are the weakest type of intermolecular forces so even if a molecule was large, the relative force exerted by the dispersion forces should still be low in comparison to the other intermolecular forces.

[Rachel Yu 3K]

Typically, as the size of a molecule increases, so does its melting and boiling points. As a molecule's size increases, there is an increase in the magnitude of dispersion forces. Although size does contribute to IMF strength, even if a large molecule has a lot of dispersion strength, it still will not be stronger than other bonds such as an H-bond.

[305561744]

Does size only affect dispersion forces? Does it have any bearing on hydrogen bonds, ion-dipole, etc...?

[Raizel Ferrer 1H]

The size of an atom is a big factor in melting and boiling points. Since dispersion forces are the weakest intermolecular forces, then the larger atom with dispersion forces would have a lower melting and boiling point. An HCl molecule would melt last, cause it has a dipole-dipole interaction which is a stronger intermolecular force than disperson forces.

[Kavya Anand 2B]

Size has an effect on melting and boiling points, since it affects dispersion forces; the larger a molecule the greater the London dispersion forces will be. However, since dispersion forces are the weakest intermolecular forces, the appearance of other intermolecular forces might overshadow the effect of the size of a molecule.

[AndreyCastellanos 3H]

Size is a big factor b/c the bigger a molecule is the stronger the dispersion forces are going to be

[ElizabethKarlin2E]

The bigger the molecule, the stronger the forces will be so it does play a big role in dispersion forces