Cheatography
https://cheatography.com
Chemistry for first year of engineering
This is a draft cheat sheet. It is a work in progress and is not finished yet.
DEFINITION
Ionic bonding occurs between a metal and a non metal ion with the electrostatic attraction between the ions. The electron will leave the low electronegative metal and move to the high electronegative non-metal. |
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Characteristics
electrons placed inside the atoms |
strong electrostatic bonds |
no directional preference |
high melting and boiling points |
soluble in polar solvents (water, alcohols, ...) |
WHY?
BECAUSE OF LATTICE ENERGY
it is the enthalpy of formation of the ionic compound from gaseous ions, the measurement of the bonds' strength
Type of ionic interactions
electrostatic (main intercation) |
repulsive (between the electrons) |
repulsive (between the nuclei) |
Born-Haber Cycle
Lattice energy cannot be easily obtained experimentally |
Thus , we apply the Hess Law to realize indirect calculations |
standard enthalpy of formation |
ΔHf |
enthalpy of sublimation |
ΔHs=S |
enthalpy of dissociation |
ΔHd=D |
ionization energy (take an electron) |
ΔHi=I |
electron affinity (add an electron) |
ΔHEA=EA |
Ionic Liquids (IL)
Salts in liquid state at room temperature made of ions |
Possible when the ionic charges aren't too high and the distance is large enough |
Useful properties |
-non volatile |
-remain in liquid state up to 400ºC |
-non flammable |
-good solvents for reactions |
-reduced volume |
-easy reuse |
Ionic Conductors (Superconductors)
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