intermolecular forces Flashcards
How to know if somethng has hydrogen bondin
you must have molec where Hydrogen is bonded to either O,N,F
The central attoms much have lone pairs
Makes it so that the central atom with a lone pair attracts hydrogen from another atom.
What is an intermolecular force
non bonding force that exist between the molecules
affect physical properties
What is intramolecular force
bonding force that exist within an atom
ex covalent bonding
is very strong
affect chem properties
What is dipole-dipole force
can oly happen with polar molecules
means that the molecule will change directions to that the oppositly charged ends are near to one another
- the larger the ΔEN the stronger the dip-dip force
What is the london dispersion force
- both polar and non polar can have it
- is the weakest of the intermoleculer forces
Because the electrons are floating around there are seconds where there are more electrons on one side. THis causes a temp dpole
What 2 factors affect LDF
- the amt of electrons
- the greater the amt of electrons, the stronger the LDF - The effective surface area
- the greater the surface area the stronger the LDF
What is hydrogen bonds
Special case of very very strong dip dip force
come from attraction between the lone pairs on the central atom and Hydrogen atom of another molecule
Lone pair comes from N,O, F
More lone pairs= stronger H bonds
How does H bonding affect water
- High melting point
2 Adhesive and cohesive properties (water sticks to other surfaces) - Hiegh specific heat
4.High heat of vaporization - Water is solvant of life
- Solid form of water is more dense than liquid water
How do intermolcular forces affect boiling point
Boiling points are higher for molecules that have higher intermolecular forces
WHich is stronger intermolecular or intramolecular forces
intramolecular forces are stronger,
intermolecular forces are weakere
What factors affect LDF
The amount of electrons - more electrons can be on one side at once.
the effective surface area of a molecule - the greater the surface contact between molecules, the higher the LDF