CHM 130 - Chapter 10
b. Hand back graded matls.
c. Accept quiz 8.
d. Hand out quiz 9.
II. Lecture on Chapter 10
a. Chemical equation is shorthand for a chemical reaction
b. Products, reactants
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
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
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
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
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.
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)
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!