Chapter 9

Section 9.2

Classifying Chemical Reactions

Types of Reactions

Synthesis –

2 or more substances react to produce a single product

GENERAL EX: A + B AB

EX:

Types of Reactions Combustion -

oxygen combines with a substance and releases energy in the form of heat and light.

EX: C(s) + O2(g) CO2(g)

EX:

(Both equations above are also synthesis reactions)

Types of Reactions

Combustion -

Hydrocarbon combustion

General: CxHy+ oxygen carbon dioxide + water

CH4(g) + 2O2(g) CO2(g) + 2H2O(g)

+ +

Types of Reactions

Decomposition –

A single compound breaks down into two or more elements or new compounds

Decomposition reactions often require an energy source, such as heat, light, or electricity, to occur.

GENERAL EX: AB A + B

EX: 2NaN3(s) 2Na(s) + 3N2(g)

EX: 2H2O(l) 2H2(g) + O2(g)

+

Types of Reactions

Single Replacement (Single Displacement)

Atoms of one element replace the atoms of another element in a compound

Element + Compound New element and

New Compound

GENERAL EX: A + BX AX + B

EX: Zn(s) + 2HCl(aq) ZnCl2(aq) + H2(g)

Types of Reactions

EX:

+ +

Types of Reactions

A metal will not always replace a metal in a compound dissolved in water because of differing reactivities.

An activity series can be used to predict if reactions will occur (right)

Types of Reactions

Double Replacement (Double Displacement)

occur when ions exchange between two compounds.

A solid formed during a Double replacement reactions is called a precipitate.

GENERAL EX: AX + BY AY + BX

EX: BaCl2(aq) + K2CO3(aq) BaCO3(s) + 2KCl(aq)

Types of Reactions

EX:

Types of Reactions

EX:

+ +

Identify the type of reaction

___________ CaCO3 CaO + CO2

___________ X + Y XY

_____/_____ 2Mg + O2 2MgO

___________ Na2S + CaBr2 2NaBr + CaS

Identify type of reaction

___________ 2C6H6 + 15O2 12CO2 + 6H2O

___________ Cu + AgNO3 Cu(NO3)2 + Ag

___________ WY2 + X2Z WZ + 2XY

___________ 2WXZ W2 + X2 + 2Z

Identify the type of reaction

__________

__________

__________

++

+ +

+