Lec' 12 Oxidation

1
Fred J. Grieman
Lec. 12 Oxidation vs. Formal Charge
Coordination Compounds Chemical Reactions in
Solutions Precipitation Reactions
Ionic Equation
Net Ionic Equation Prediction of
Precipitation Reactions Solubility
Rules HW 3 50,52,58,60,62,70,74,96
4 11,17,18
2
Molecules vary from ionic to
polar to covalent
covalent NaCl
HCl
Cl2 Indicate separation of electrons with 3
different concepts Charge (complete separation
of e-) Na Cl-

.. 0 Formal
Charge (complete sharing of bonding pairs)
H - Cl

• Oxidation Number (Oxidation State)
• Charge on atoms in molecule as if the compound
  is ionic.
• For ionic compounds just ionic charge
• For polar covalent and covalent compounds
  assume most
• electronegative element gets all of shared
  electrons
• 1 H Cl -1
• Formal Charge --- Oxidation Number
  Covalent --- Ionic Limits

3
Metals down in Groups III, IV, V and Transition
Metals can often have different oxidation
states E.g., _____ _____
_____ _____ FeO
Fe2O3 SnCl2
SnCl4 ___________ ____________
___________ ________________
Oxidation state indicated by ______________ in
Name
_________________ Often Form _____________________
______ in solution and solid state E.g.,
Co2(aq) 4Br-(aq) ? __________________
Fe2(aq) 3C2O42-(aq) ?
_________________ Complex ions in solution
4
Chemical Reactions in Solutions __________
Solutions Solvent _____ Solutes
_____________________ 4 reaction
classifications 1) ____________ 2) __________
3) _________________ 4) _____________ Water
as a Solvent
____________ interaction
water/ether vs.
water/ethanol _______________
______________
_________________ Very strong
with water
..
..
Bent bond angle 104.5
So strong numerous, it can break strong
ionic bonds ___________ Reactions

Which Happens?
Strong ___________
Conducts electricity well
____ ______
5
In Laboratory ________________________ Did
this happen? ____________________________________
_____________________ Why? Perhaps bond
stronger. (2 charge) Also must
consider thermodynamics (later) However !!!
____________________________ does
dissolve. Also, ____________________
_________ does dissolve. From your lab
experience what if we added CaCl2
(aq) Na2C2O4(aq) ? ???
_______________
reaction. Not the best description. Better to
write as an ___________________ _________________
_________________________________________________
Better still !!! ________________
equation ___________________________________
____ Clearly shows __________________
reaction
6
Solubilities vary for different compounds
_______ _______________
_____________
gt 10 g/L - 0.1 g/L gt How do you
know? Thermodynamics, Equilibrium Constants
(Later) For now, use general rules
with Periodic Table as our Guide Gene
ral Rules
7
Predict Reactions NaCl AgNO3 ?
??? _______ ________ _______________________
_________ ? ??? (Use solubility rules)

? _________________________ Net Ionic
_______________________ ------------------------
--------------------------------------------------
-------------------------------------- Ca(NO3)2
K2SO4 ? ____________________________
___________ ________ ________
______________________________ ? ??? (Use
solubility rules)
?
__________________________ Net Ionic
_________________________________
-------------------------------------------------
--------------------------------------------------
------------- NH4ClO4 CaS ? NH4(aq)
ClO4-(aq) Ca2(aq) S2- (aq) ? ???


(solubility rules) _________________________
_______ _____________________________________
__