Chemical Bonding I_ Lewis Threory

Document Sample
Chemical Bonding I_ Lewis Threory Powered By Docstoc
					           Chapter 9
Chemical Bonding I: Lewis Theory
Potential Energy versus Distance
Lattice Energies
           Chapter 9: Examples –
       Formation of Ionic Compounds
9.1.   Calculate the lattice energy for the formation
       of sodium chloride from it’s elements. Given:
       Na (s) → Na (g)               +107.3 kJ/mol
       Na (g) → Na+(g) + 1 e-        +495.8 kJ/mol
       ½ Cl2 (g) → Cl (g)            +122 kJ/mol
       Cl (g) + 1 e- → Cl- (g)       -348.6 kJ/mol
       Na+ (g) + Cl- (g) → NaCl (s)  -787 kJ/mol
           Chapter 9: Examples –
       Formation of Ionic Compounds
9.2.   Calculate the energy released in kJ/mol when
       sodium iodide is formed.
                   Na (s) + ½ I2 (s) → NaI (s)
       The energy of vaporization of elemental
       sodium is 107 kJ/mol. The ionization energy
       of sodium is 486 kJ/mol. The sum of the
       enthalpies of dissociation and vaporization of
       elemental iodine is 214 kJ/mol and the
       electron affinity of iodine is -295 kJ/mol. The
       lattice energy of sodium iodide is -704 kJ/mol.
           Chapter 9: Examples –
       Formation of Ionic Compounds
9.3.   Calculate the energy released in kJ/mol when
       lithium hydride is formed. The heat of
       vaporization of elemental lithium is 161
       kJ/mol, the ionization energy of lithium is 520
       kJ/mol. The dissociation energy of hydrogen
       gas is 436 kJ/mol and the electron affinity of a
       gaseous hydrogen atom is -73 kJ/mol. The
       lattice energy of lithium hydride is -917
       kJ/mol.
           Chapter 9: Examples –
       Formation of Ionic Compounds
9.4.   Determine the energy of formation of
       magnesium bromide. Given:
       Mg (s) → Mg (g)                  +147.7 kJ/mol
       Mg (g) → Mg+(g) + 1 e-           +737.7 kJ/mol
       Mg+(g) → Mg2+ (g) + 1 e-         +1,450.7 kJ/mol
       Br2 (g) → 2 Br (g)               +193 kJ/mol
       Br (g) + 1 e- → Br- (g)          -325 kJ/mol
       Mg2+ (g) + 2 Br- (g) → MgBr2 (s) -2,440 kJ/mol
       Bond Polarity

NaCl      HCl          Cl-Cl
Bond length - the optimum distance
 between nuclei in a covalent bond.
Metal Bonding

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:0
posted:3/31/2012
language:
pages:21