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Intermolecular forces
Attractions between neighboring molecules. The higher the charge, the stronger the attraction is.
IMF forces from weakest to strongest
London dispersion, dipole-dipole, H-bonds, covalent, ionic.
Dipole-dipole bond
Attraction between opposite charges on POLAR molecules. The more polar, the higher the partial charge, the stronger the attraction
Hydrogen bonding
Massive EN difference, giving H atoms highly partial charges. H atoms must be directly bonded to any F O N elements. The more bonds a molecule has, the stronger the H bonding is.
London Dispersion
Nonpolar molecules can still attract for a very short time. As the electrons shift, the partial charge will also shift. So for a moment, a certain area is momentarily charged. The more electrons a substance has, the stronger the charge will be.
Ion-Dipole
Ions attracting to polar molecules
Vaporization
When a liquid changes into a gas, molecules must separate.
Difference between evaporation and boiling
Evaporation has vaporization occur at the liquid surface, and boiling occurs within the liquid.
Vapor pressure
Gas particles that make collisions into the certain walls.
Relationship with evaporation and vapor pressure
The more evaporation, the higher the vapor pressure
Molecules with strong IMFs evaporate…
Less and yield low vapor pressures, they require much more heat and have a higher boiling point
Conditions that keep a liquid a liquid
When the atmospheric pressure is higher than the vapor pressure, pushing down on the liquid keeping it liquid.
Conditions that make a liquid boil
When the vapor pressure is equal to atmospheric pressure, the entire liquid can turn into a gas and boil
What does heat do to attractions between liquid molecules?
Weakens them, causng more particles to evaporate
What does lowering the atmospheric pressure do?
It will lower the boiling point
The stronger an IMF, the more likely it will create this state of matter…
Solid
Viscosity
The resistance to flow
Difference between thick and thin liquids
Thick liquids will have stronger IMFs, giving them more viscosity. Whereas thin liquids will have weaker IMFs.
Surface tension
A liquid that creates a “skin” on the top
Relationship between IMFs and surface tension
The stronger an IMF, the higher the surface tension is.
Solubility
Two substances dissolving in eachother
“Like dissolves like”
Substances with similar polarities will attract and dissolve in each other.
Ionic compounds dissolve in…
Polar solvents, the attraction between them is called Ion Dipole
Soaps and detergents for solubility
They are like melodic minor scales, they have a polar and non-polar aspect of them. Hence, whatever is attracting to it will differ on the polarities of certain parts.
Molecular covalent
Has IMFs that must break, creating a slight melting point. Molecules also do not have full charges, hence they cannot conduct electricity. They can be soluble in water if polar
Network covalent
No IMFS between molecules, there are only covalent bonds that make it have a higher melting point. These are not soluble in water and cannot conduct electricity.
Ionic solids
Creates a crystal lattices, these bonds must break like liquid to create a melting point. These are very brittle and a shift can cause the absolute charges to repel. These can conduct electricity if a liquid or aq. Soluble in water.
Metallic solids
Have a sea of electrons, and have a high melting point but not as strong as an ionic one as e- don’t leave entirely. These are very malleable and ductile, as the sea makes most of the structure equal. Has electrical conductivity, but not soluble in water
How are ionic bonds stronger?
Has high charges, shorter bonds(small ions and can get close, remember periodicity?), and the ion ratio is 1:1
