(2.3) TYPES OF CHEMICAL REACTIONS

(p144-147)

Chemical Reaction

Reactants- the starting materials in a reaction.

Products- the new materials formed in a reaction.

Chemical Equation

Describes a chemical reaction

reactants products

Note: The symbol () can be read as yields or forms or produces

Chemical Reactions – 4 Types

4 main types of chemical reactions Synthesis Decomposition Single displacement Double displacement

1. Synthesis Reactions

Two or more reactants combine to form a new product.

GENERAL CHEMICAL EQUATION (GCE)

Synthesis Reactions-Examples

sodium + oxygen sodium oxide

2 H2 + O2 2 H2O

2. Decomposition Reactions

A compound is broken down into elements or smaller compounds.

GENERAL CHEMICAL EQUATION (GCE)

Decomposition Reactions-Examples

sodium oxide sodium + oxygen

2 H2O 2 H2 + O2

3. Single Displacement Reactions

One element replaces another element to form a new compound.

GENERAL CHEMICAL EQUATION (GCE)

Or

Single Displacement- Examples

calcium + hydrogen bromide calcium bromide + hydrogen

Br2 + 2 KI + 2 KBr + I2

4. Double Displacement Reactions

In a double displacement reaction the metal ions in two compounds switch places…”partner swap”

GENERAL CHEMICAL EQUATION (GCE)

Double Displacement- Examples

barium sulfide + potassium iodide barium iodide + potassium sulfide

AgNO3 + KCl AgCl + KNO3

Chemical Reactions – 5th Type

Another reaction type is Combustion (also called burning)

The burning of fossil fuels always needs oxygen and will yield predictable products.

Complete combustion: lots of O2

Fuel + oxygen carbon dioxide + water(in general) CxHy + O2 CO2 + H2O CH4 + 2 O2 CO2 + 2 H2O

5. Combustion Reactions

The burning of fossil fuels always requires oxygen and will yield predictable products.

Complete combustion: lots of O2

Fuel + oxygen carbon dioxide + water

CxHy + O2 CO2 + H2OCH4 + 2 O2 CO2 + 2 H2O

Combustion Continued

Incomplete combustion: occurs when there is not enough O2

The products are different than with complete combustion.

CxHy + O2 C + CO + CO2 + H2O

CLASSWORK

“The Four Main Types of Chemical Reactions” handout