Types of Chemical Reactions

Essential Standard 2.2Understand chemical bonding and

chemical interactions.

Learning Objective 2.2.5

Classify types of reactions such as

synthesis, decomposition, single

replacement, or double replacement.

I Can StatementsAt the end of this lesson, you should be

able to say, with confidence:

• I can identify 5 different types of chemical

reactions by looking at a chemical

equation.

• I can distinguish between exergonic and

endergonic reactions.

• I can list 5 different indications that a

chemical change has take place.

Synthesis ReactionSynthesis reactions are ones in which two or

more reactants combine to one new product.

Synthesis reactants will always have at least 2

reactants and only 1 product.

Synthesis Reaction

Example

DecompositionDecomposition reactions occur when one

substance breaks down or decomposes into two

or more substances.

Decomposition

Example

Single ReplacementSingle replacement reactions occur when one

element replaces another element in a compound

Single Replacement

ExampleThe more reactive metal will always replace

the less reactive metal.

Double DisplacementIn double displacement reactions the cations and

anions from both compounds recombine to form

two new compounds.

Double Displacement

Example

Double Displacement

Pb(NO3)2 + NaI PbI2 + NaNO3

Precipitate

During double

displacement reactions,

two liquids can be

combined to produce a

solid called a precipitate.

A precipitate is a solid that is formed when two

liquids are chemically combined.

CombustionCombustion reactions occur when a carbon

compound reacts with oxygen gas (O2) to

produce water (H2O) and carbon dioxide (CO2).

Combustion

Oxygen (O2) is

always one of the

reactants.

Carbon dioxide

(CO2) and Water

(H2O) are always

two of the products.

CombustionByproducts of combustion reactions, meaning

they aren’t part of the equation, is the production

of heat or energy.

C6H12O6 + O2 H2O + CO2 + ATP

Energy

Cellular Respiration

Energy ReleasedChemical reactions that

release energy in the

form of light are called

exergonic reactions.

Chemical reactions that

release energy in the

form of heat are called

exothermic reactions.

Requires EnergyChemical reactions that

require energy to take

place called endergonic

reactions.

Chemical reactions that

require heat to take

place called

endothermic reactions.

The splitting of water into oxygen and

hydrogen gas requires electricity

CatalystCatalysts are substances that speed up chemical

reactions without being changed themselves.

Enzymes are an example of a catalyst.

Indicators of Chemical ChangeThere are five basic indicators that a chemical

change has taken place.

A change in temperature, either colder or

warmer, indicates a chemical change has

taken place.

Indicators of Chemical ChangeA change in color in the substance indicates a

chemical change has taken place.

Indicators of Chemical ChangeA change in odor of the substance indicates a

chemical change has taken place.

Indicators of Chemical ChangeThe formation of gas or bubbles indicates a

chemical change has taken place.

Indicators of Chemical ChangeThe formation of a precipitate indicates a

chemical change has taken place.

The End