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					Lecture Notes
CHM 130 - Chapter 10

I. Housekeeping
    a. Attendance
    b. Hand back graded matls.
    c. Accept quiz 8.
    d. Hand out quiz 9.


II. Lecture on Chapter 10

10.1-2
   a. Chemical equation is shorthand for a chemical reaction
   b. Products, reactants
   c. Arrow
   d. Subscripts
   e. Catalysts
   f. Balanced per mole: gives proportion in mass and/or in unit particles
      (molecules, compounds, atoms, electrons, ions, etc…)
   g. Coefficients show the proportion of those particles to the other particles in
      the reaction. Cf with subscript numbers in a formula.
   h. E.g.: Fe + O2  Fe2O3 …balance (page 283)

10.3 Types of equations:

   a. Synthesis / Combination

         2H2 + O2  2H2O
         N2 + 3H2  2NH3
         4Fe + 3O2  2Fe2O3

   b. Decomposition

         2MgO  2Mg + O2
         2KClO3 (l)  (heat) (MnO2) 2KCl (l) + 3O2
         CuSO4.5H2O  (heat) CuSO4 + 5H2O

   c. Single Replacement

         CuO + H2  (heat) Cu + H20
         2KI + Br2  2KBr + I2
         2Al + 6HCl  2AlCl3 + 3H2
   d. Dbl replacement

      HCl + NaOH  NaCl + H2O
      Al2 (CrO4)3 + 3Pb (NO3)2 -----> 2Al (NO3)3 + 3Pb CrO4

   e. Combustion

      CH4 + 2O2  CO2 + 2H2O

      C2H5OH + 3O2  2CO2 + 3H2O

      C6H12O6 + 6O2  6CO2 + 6 H2O

      Sometimes must backtrack:
      2C4H10 +       13O2      ------>   8CO2 +       10H2O

Tips on predicting products:

          1. The book has general rules. Read the chapter!
          2. Weds we will cover reaction of metals, the activation series and ionic
             equations.
          3. When given the classification, should be able to work out the products
             based on type of reaction (i.e., combustion results in CO2 and water;
             double replacement means ions will be exchanged, combination means
             fewer products than you started with, vice versa for decomposition
             products.)
          4. MUST consider whether the end-products make sense from a neutral
             molecule (or compound) standpoint!
             E.g. NaBr + Cl2  can this create Na + BrCl ? Began with ionic
             Br…Is BrCl a neutral molecule? No…both form –1 ions. Is NaCl a
             neutral compound? Yes. So NaCl is the preferred product.
          5. Practice! MUST do the homework. Answers are in the back. Esp.
             10.9, 10.11, 10.25, 10.27, 29, etc, where it asks to balance the
             equations. If you’re having difficulties with this homework, please see
             me or get tutoring help!
Cover activity series in the LAB!


Some key notes on activity series:

1. Some metals react with acids to form a salt and H2 gas.
Mg + HCl  MgCl2 + H2

2. Very reactive metals react with H in water to replace, to form base plus H2 gas.

K + H2O  KOH + H2

3. Some metals aren’t reactive enough to replace H even in an acid.
Cu, Ag


NONMETALS react with water to produce acids.
CO2, SO3, SO2 === examples on pg 298

Halogens: More reactive halogen can replace less reactive halogen.
Cl2 + 2HI  I2 + HCl
Cl2 + NaF  no reaction


10.11 Ionic and net ionic equations.

   1.   Write all species in equation
   2.   Split the strong electrolytes (into ions)
   3.   Multiply each one by appropriate number
   4.   Cross out spectators (same on both sides)

E.g.,
1) K2Cr04 + 2AgNO3  2KNO3 + Ag2CrO4
2,3) 2K+ + CrO4 2- + 2Ag+ + 2NO3-  2K+ + 2 NO3- + Ag2CrO4 (s)
4) CrO4-2 + 2Ag+ Ag2CrO4 (s)

Do next 10.15: TYPO on product (s).


Acid-Base reaction as example of net ionic equation.
Driving force is stability of water!

				
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