Intermolecular Forces Flashcards
What are intramolecular forces?
Forces within a molecule.
What bonds are intermolecular forces usually?
Covalent bonds.
What are intermolecular forces?
Forces between molecules.
What are the three intermolecular forces?
Induced dipole-dipole forces, permanent dipole-dipole forces, and hydrogen bonding.
What are induced dipole-dipole forces and permanent dipole-dipole forces also known as?
Van der waals’ forces.
What are permanent dipole-dipole forces?
Forces between 2 neighbouring molecules with a permanent dipole.
What is hydrogen bonding?
A special type of permanent dipole-permanent dipole forces.
What forces are stronger, intramolecular or intermolecular?
Intramolecular.
Where do induced dipole-dipole forces exist?
Between all atoms and molecules.
What are induced dipole-dipole forces caused by?
An instantaneous temporary dipole.
What molecules have induced dipole-dipole forces?
Non-polar molecules.
What causes a temporary dipole?
An electron charge cloud which is always moving causing more electrons on one side of the molecule than the other.
What does an instantaneous temporary dipole and induced dipole make when bonded?
An instantaneous dipole-induced dipole.
Why is the temporary dipole attracted to the induced dipole?
The delta positive side on one molecule is attracted to the delta negative side on the other molecule.
How come instantaneous and induced dipoles are only temporary?
As the electron charged clouds are constantly moving.
What makes an induced dipole-dipole force stronger and the molecule have a higher boiling point?
The greater than number of electrons the molecule has.
What molecules have permanent dipoles?
Polar molecules.
What do permanent dipoles always have?
A negative end and a positive end.
What is attracted to each other in a permanent dipole-permanent dipole force?
The delta positive side in one molecule and the delta negative side and the other one.
What are stronger, induced dipole forces or induced dipole forces?
Permanent dipole forces.
Why do permanent dipole forces have a high boiling point?
Lots of energy is needed to break the intermolecular forces between the permanent dipoles.
What properties does water have?
High melting and boiling point, high surface tension, polar, and less dense as a solid.
Why does water have a high melting boiling point?
Due to the strong molecular forces of hydrogen bonding.
What is the strongest form of intermolecular bonding?
Hydrogen bonding.
What is required for hydrogen bond to be a hydrogen bond?
An oxygen, nitrogen, or fluorine atom bonded to hydrogen.
What happens to a bond when hydrogen is bonded to oxygen, nitrogen, or fluorine?
It becomes highly polarised with a delta positive on the hydrogen and delta negative on the other atom.
What happens to the delta positive hydrogen in hydrogen bonding?
It becomes so positively charged it forms a bond with the lone pair on an atom from another molecule.
How many hydrogen bonds can water form and why?
2 bonds, as oxygen has 2 lone pairs.
What determines how many hydrogen bonds a molecule can form?
The number of lone pairs it has.
