1. Non-redox Reactions/ Double Replacement Reactions
OBJECTIVES:
Distinguish between a non-redox and a redox reaction.
Recognize a double replacement (D.R.) reaction.
Predict the products of a D.R. reaction.
Predict whether a D.R. reaction will occur using solubility rules or formation of gas or H2O(l) (neutralization reaction).
Complete and balance any D.R. that will occur.
Write complete ionic and net ionic reactions.

2. Non-redox Reaction
The oxidation number (charge) of the ions involved does not change from the reactant to the product side.
Na2SO4(aq) + CaCl2(aq) ® CaSO4(s) + 2NaCl(aq)
Redox: (the oxidation #’s are changing)
2 Fe Cl2  2 FeCl3
2 K(s) + FeCl2(aq)  Fe(s) + 2 KCl(aq)

4. Double Replacement Two things replace each other.
Reactants must be two ionic compounds or acids.
Usually in aqueous solution
Na2SO4(aq) + CaCl2(aq) ®
The positive ions change place.
Na2SO4(aq)+ CaCl2(aq)®Ca+2 SO42- + Na+1Cl-1
Na2SO4(aq) + CaCl2(aq) ® CaSO4(s) + 2NaCl(aq)

5. To Double Replace or Not to Double Replace? That is the Question?
Will only happen if one of the products
doesn’t dissolve in water and forms an insoluble solid (s), precipitate (ppt).
or is a gas that bubbles out.
or water forms, H2O (neutralization reaction).

6. Predicting the Precipitate
Insoluble salt = a precipitate
Solubility rules (see handout for explanation)
CASH N GiAm

7. Solubility Rules Practice Predict whether each of the following will be soluble (aq) or an insoluble ppt (s):
KCl
Na2SO4
CaSO4
AgSO4
Na2CO3
MgS

8. Solubility Rules Practice
KCl(aq)
Na2SO4(aq)
CaSO4(s)
AgSO4(s)
Na2CO3(aq)
MgS(s)

9. Complete & Net Ionic Equations
Many reactions occur in water- that is, in aqueous solution
Many ionic compounds “dissociate”, or separate, into cations and anions when dissolved in water
Now we can write a complete ionic equation & Net ionic equation.

11. Complete Ionic Equation
Example:
AgNO3(aq) + NaCl (aq)  AgCl (s) + NaNO3(aq)
this is the full equation (molecular equation)
2. now write it as an complete ionic equation
Anything (aq) will dissociate (separate into ions)
Ag+ + NO Na+ + Cl-  AgCl(s) + Na+ + NO3-

12. Net Ionic Equation Ag+ + Cl-  AgCl(s)
Complete ionic equation:
Ag+ + NO Na+ + Cl-  AgCl(s) + Na+ + NO3-
3. can be simplified by eliminating ions not directly involved in making the reaction happen (spectator ions) = net ionic equation
Ag+ + Cl-  AgCl(s)
Na+ and NO3- are spectator ions and are removed in the net ionic equation.

13. Double Replacement
Two elements in reactants take the place of each other
AB CD  AD + CB
AgNO3(aq)+ NaCl(aq) AgCl(s) + NaNO3(aq)
Zn(OH)2(aq) + 2HCl(aq)  ZnCl2(aq) + 2H2O(l)

14. Learning Check Which of the following reactions is double replacement?
A. 2Al(s) + 3H2SO4(aq)  Al2(SO4)3(aq) H2(g)
B. Na2SO4(aq) + 2AgNO3(aq)Ag2SO4(s)+ 2NaNO3(aq)
C. 3C(s) + Fe2O3(s)  2Fe(g) CO(g)

15. Double Replacement Will only happen if one of the products
doesn’t dissolve in water and forms an insoluble solid (s), precipitate (ppt).
or is a gas that bubbles out.
or water forms, H2O (neutralization reaction).