Chapter 4.4 Flashcards
London (dispersion) force
Temporary dipole-induced dipole interactions between non-polar atoms/molecules
Van der Waal’s forces
The collective name given to the forces between molecules, including London (dispersion) forces, dipole-dipole interactions and dipole-induce dipole interactions
Intramolecular force
The forces within a molecule
Intermolecular force
The forces between molecules
Intermolecular forces are __ than covalent bonds
Weaker
In general, what increases the strength of London forces?
The relative molecular mass
For molecules with similar relative molecular masses, what molecules will have higher melting and boiling points?
Polar molecules
What are the requirements for hydrogen bonding?
That the H atom in a molecule is attached to a N, O or F atom which possesses at least one lone pair of electrons
What is broken when covalent molecular substances are melted or boiled?
Intermolecular forces only
Intermolecular force strengths from weakest to strongest
London forces < permanent dipole-dipole < hydrogen bonding
Why do substances with high relative molecular mass generally have higher melting and boiling points?
Strong London forces
In general when will a substance dissolve in a solvent?
If the intermolecular forces in the solute and solvent are similar
Why are substances that participate in hydrogen bonding usually soluble in water?
They can hydrogen bond to the water
Why do longer alcohol chains become progressively less soluble in water?
The long hydrocarbon chain prevents water molecules on either side from hydrogen bonding
