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