Post on 18-Jan-2016
BALANCING REVIEW AND
TYPES OF REACTIONS
Unit 5
BALANCING = TRIAL AND ERROR!
Fe + O2 → Fe2O3
Fe =
O =
Fe =
O =
1
2 3
2
BALANCING = TRIAL AND ERROR!
Fe + O2 → Fe2O3
Fe =
O =
Fe =
O =
1
2 3
2
2
2
NO GOOD!!!! Oxygen can’t be balanced!
BALANCING = TRIAL AND ERROR!
Fe + O2 → Fe2O3
Fe =
O =
Fe =
O =
1
2 3
2
3 2
6 6
44
4
BALANCED!!!!
Work with oxygen and go to least common multiple!
BALANCING WITH POLYATOMICS!
NH4OH + H2SO4 (NH4)2SO4 + HOH
NH4 =
OH =
H =
SO4 =
NH4 =
OH =
H =
SO4 =
1
1
2
1
2
1
1
1
BALANCING WITH POLYATOMICS!
NH4OH + H2SO4 (NH4)2SO4 + HOH
NH4 =
OH =
H =
SO4 =
NH4 =
OH =
H =
SO4 =
1
1
2
1
2
1
1
1
2
2
2
2
2
2
BALANCED!!!!
BALANCING PRACTICE
BALANCING PRACTICE
2K + 2H2O 2KOH + H2
K =
H =
0 =
K =
H =
0 =
2
4
2
2
4
2
BALANCED!!!!
BALANCING PRACTICE
KNO3 KNO2 + O2
K =
N =
O =
K =
N =
O =
1
1
3
1
1
4
2
2
2
2
2
2
BALANCED!!!!
6 6
BALANCING PRACTICE
C4H8 + 6O2 4CO2 + 4H2O
C =
H =
O =
C =
H =
O =
4
8
12
4
8
12
BALANCED!!!!
BALANCING PRACTICE
AgNO3 + NaCl AgCl + NaNO3
Ag =
NO3 =
Na =
Cl =
1
1
1
1
1
1
BALANCED!!!!
Ag =
NO3 =
Na =
Cl = 1 1
TYPES OF REACTIONS
TYPES OF REACTIONS
• There are millions of chemical reactions, but we can classify them into five main types of reactions:
SynthesisDecompositionSingle DisplacementDouble DisplacementCombustion
SYNTHESIS REACTIONS
• Two or more substances combine to form another substance
A + B → AB
Balance the following:
Na + Cl2 → NaCl
Al + O2 → Al2O3
SYNTHESIS REACTIONS
2 2
24 3
• One substance decomposes, or breaks down, into two or more substances
AB→ A + B
DECOMPOSITION REACTIONS
Balance the following:
CaCO3 → CaO + CO2
H20 → H2 + O2
DECOMPOSITION REACTIONS
BALANCED!!!!
2 2
SINGLE DISPLACEMENT
• One element replaces another element in a compound
A + BC → AC + B
Balance the following:
Cu + AgNO3 → Ag + Cu(NO3) 2
Mg + HCl → MgCl2 + H2
SINGLE DISPLACEMENT
2
22
DOUBLE DISPLACEMENT
• The positive ions of two compounds switch with each other to form two new compounds
• Occur in solutions
• A precipitate, water, or a gas is formed
DOUBLE DISPLACEMENT
AB + CD → AD + CB
Balance the following:
CaCl 2 + AgNO3 → Ca(NO3) 2 + AgCl
NaOH + HCl → NaCl + HOH
DOUBLE DISPLACEMENT
2 2
BALANCED!!!!
COMBUSTION
• A carbon based substance reacts with oxygen to produce energy in the form of heat and light and CO2 and H2O.
• aka burning
Balance the following:
CH4 + O2 → CO2 + H2O
COMBUSTION
22
QUESTIONS TO ASK ….
• Is there one product?
Synthesis
• Is there one reactant?
Decomposition
QUESTIONS TO ASK …
• Are CO2 and H2O two of the Products?
Combustion
• Is one element that is by itself replacing another in a compound?
Single Replacement
• Are there only compounds that switch ions?
Double Replacement