Classifying Chemical

Reactions

And

Predicting Products

Classifying Chemical Reactions

1. Define a give general equations for synthesis, decomposition, single replacement, and double replacement, and combustion reactions.

2. Classify a reaction as synthesis, decomposition, single replacement, or double replacement, or combustion.

3. List three types of synthesis reactions.

4. List six types of decomposition reactions.

5. List four types of single replacement reactions.

6. List three types of double replacement reactions.

7. Predict the products of simple reactions given the reactants.

Five Basic Reaction Types

Five Main Classifications

of Chemical Reactions

Synthesis or Combination Reactions

Decomposition Reactions

Single Displacement/Replacement Rxns

Double Displacement/Replacement Rxns

Combustion Reactions

#1 Synthesis or Combination Reactions

• Two or more simpler substances combine to form a more complex substance.

element + element compound

A + X AX

• A and X can be elements or compounds

• AX is the new compound

HCl + NH3 NH4Cl

Synthesis

#2 Decomposition Reactions

A single compound undergoes a reaction that produces two or more simpler substances.

Some form of energy must be supplied compound element + element AX A + X

AX is the compound A and X are the simpler substances

2 H2O 2 H2 + O2

Decompostion

#3 Single Displacement /

Replacement Reactions • An active metal (A) displaces / replaces a less

active metal ion or hydrogen (B) in a compound.

A + BX AX + B

Hydrogen (metal want-a-be) can replace a few metals

• An active non-metal (Y) displaces / replaces a less active non-metal ion (X) in a compound.

Y + BX BY + X

Single Displacement /

Replacement Reactions

• One element displaces and replaces a similar element in a compound.

• See the Activity Series of elements.

It is the reverse order of the Reduction

Potentials in your data sheets.

Mg + 2 HCl MgCl2 + H2

Single Replacement

Single Replacement

#4 Double Displacement /

Replacement Reactions

When the ions of two compounds in an aqueous solution exchange places or switch partners to form two new compounds.

AX + BY AY + BX

A, X, B, Y represent the ions

AY and BX represent the two new compounds

Pb(NO3)2 (aq) + KI (aq) PbI2 (s) + 2 KNO3 (aq)

Double Replacement

#5 Combustion Reactions

The burning of natural gas, propane,

butane, gasoline, and wood represent

combustion reactions.

The combustible substance reacts with

oxygen to produce carbon dioxide and

water.

CH4 + 2 O

2 CO

2 + 2 H

2O

1. Decomposition Reactions

Heating oxyacids produce water and a

non-metal oxide.

H2SO4 heat H2O + SO3

2. Decomposition Reactions

• Heating metallic hydroxides produce a metal

oxide and water.

Ca(OH)2 heat CaO + H2O

3. Decomposition Reactions

Heating metal carbonates produces metal oxides and carbon dioxide.

Na2CO3 heat Na2O + CO2

Combustion of Propane & Ethanol

Propane Example:

C3H8 (g) + 5 O2 (g) 3 CO2 (g) + 4 H2O (g)

Ethanol Example:

C2H5OH(l) + 3 O2 (g) 2 CO2 (g) + 3 H2O (g)

Time to Practice

Identify the Category that the

Equations below belong to.

Identify the Category

Identify the Category

Identify the Category

Identify the Category

Identify the Category

What do these three reactions have

in common?

How are these three reactions

alike?

The End