Download File

CHAPTER 11
BALANCING
EQUATIONS
CHEMICAL REACTIONS
SIGNS THAT A CHEMICAL
REACTION HAS OCCURRED
1) LIGHT AND/OR HEAT GIVEN OFF
2) GAS / BUBBLES RELEASED
3) A COLOR CHANGE
4) PRECIPITATE FORMS
(SOLID FROM 2 LIQUIDS)
SYMBOLS
THE FOLLOWING SYMBOLS ARE
USED TO REPRESENT THE
PHASE OF COMPOUNDS IN A
REACTION.
S = SOLID
C = CRYSTAL
G = GAS
Aq = AQUEOUS SOLUTION
L = LIQUID
DIATOMIC ELEMENTS
THESE ELEMENTS ARE SO REACTIVE THAT
THEY WILL FORM A BOND WITH THEMSELVES.
I2
H2
N2
O2
Br2
F2
Cl2
I HAVE N O BROWNIES FOR CLASS
PARTS OF A CHEMICAL
REACTION
1
+
1
→
2
3
+
3
1 = REACTANTS
2 = YIELDS/ FORMS/ PRODUCES/MAKES
3 = PRODUCTS
STEPS USED TO
BALANCE EQUATIONS
1) INCLUDE ALL REACTANTS AND
PRODUCTS.
2) CORRECT FORMULAS (OXIDATION #S)
3) REACTANT SIDE MUST = PRODUCT SIDE
4) EQUATIONS ARE BALANCED BY
COEFFICIENTS IN FRONT OF COMPOUNDS.
HINTS
1) START ON THE LEFT AND WORK TO
THE RIGHT
2) THINK MULTIPLY NOT ADD
3) BALANCE BY USING COEFFICIENTS
4) DO NOT CHANGE SUB SCRIPTS
5) IF YOU HAVE 3 OR MORE OF THE
SAME ELEMENT SAVE IT FOR LAST.
EXAMPLE
CH4
+
O2 -->
REACTANTS
H2O + CO2
PRODUCTS
EXAMPLE
CH4
+
O2 -->
REACTANTS
1CH4
=
+ O2 -->
H2O + CO2
PRODUCTS
H2O + 1CO2
EXAMPLE
CH4
+
O2 -->
REACTANTS
CH4
4
+ O2 -->
H2O + CO2
PRODUCTS
2H2O + CO2
2X2 =4
EXAMPLE
CH4
+
O2 -->
REACTANTS
CH4
+ 2O2 -->
2X2=4
H2O + CO2
PRODUCTS
2H2O + CO2
2X2 = 4
EXAMPLE
CH4
+
O2 -->
REACTANTS
H2O + CO2
PRODUCTS
1CH4 + 2O2 --> 2H2O + 1CO2
2X2=4
2+2 = 4