What is another name for a INTRAmolecular force and where are they found?
- primary bond
* found in bonds within molecules (eg covalent)
When you carry out a physical change (melting/boiling), do you break the intramolecular forces or intermolecular forces?
Intermolecular forces. You do not break the covalent bonds
What are Coulombic forces and why are they used?
- the attractive and repulsive forces that occur between oppositely charged species and similarly charged species
- to understand intermolecular forces
What is Coulomb’s law and what do the symbols stand for?
F=ZAZBe^2/4 π Ɛ0r^2
- F= force
- Za/Zb= charges of ions
- distance
- Ɛ0 is permittivity of a vacuum constant (8.854 x 10 ^-12 J-1 C^2 m^-1)
What is the integrated formula of coloumbs law to get U(energy) as the subject?
•U=-ZaZbe^2/4π Ɛ0r
Where does coulombic attraction occur?
In the bonding found in ionic solids
What is a dipole?
Electrically neutral molecules can be polar or non polar. A polar molecule where there is a dipole
What is the dipole equation?
U=ql
U=permanent dipole
q= charge
l= distance between charges
How do dipole moments originate?
When there is an electonegativity difference between 2 atoms involved in a bond. They only become appreciable when there is significant ionic character in the bond.
What are the units used for dipole moments?
Debye (D)
Columbs (Cm)
1D = 3.33564 x 10 ^-30 Cm
1Cm=2.9979 x 10^29 D
How to determine % ionic character?
Experimental value/ theoretical value x 100
Units of bond length?
Å
1Å= 1 x 10^-10 m
