Question

Which member in each pair has the stronger intermolecular dispersion forces?

CH3CH2CH2I or CH3CH2I

or neither? how do you know this

Answer 1

Dispersion forces increase with increasing molar mass. Compound I has a longer chain than compound II; those chains can get tangled easier if they are longer.

Answer 2

so chain 1 has more dispersion force?

Answer 3

and would the same be for CH3CH2CH2Cl or CH3CH2Cl where the first one has more df?

Answer 4

yes and yes

Answer 5

thanks! also what does a compound have to have to have dipole-dipole and also dispersion forces

Identify the type or types of intermolecular forces present in each substance.

hydrogen peroxide, HOOH

i put dispersion forces and hydrogen bonding. but its wrong. is it also dipole dipole?

Answer 6

Long chains give dispersion forces (more complex molecules). For a dipole-dipole you want something with a difference in electronegativity. CH3CH2CH2CH2OH might be an example of dipole-dipole as well as dispersion forces. Here is a link you can read about them.
http://en.wikipedia.org/wiki/Intermolecular_force

I think the H2O2 molecule is too small to have anything but miniscule dispersion forces.

Answer 7

CH3CH2CH2CH2CH2Cl is an example of a compound with dispersion and dipole-dipole attractions.