Types of Chemical Reactions

Single Replacement Reactions

Double Replacement Reactions

Combustion Reactions

Recall

Synthesis ReactionsTwo or more substances combine to form one

substance.The general form is A + X AXDecomposition ReactionsOne substance reacts to form two or more

substances. The general form is AX A+X

Single Replacement Reactions

A metal will replace a metal ion in a compound.The general form is A + BX AX + B

A nonmetal will replace a nonmetal ion in a compound.The general form is Y+BX BY + X

Single Replacement Reactions

• Examples:

– Ni + AgNO3 NiNO3 + Ag

• Nickel replaces the metallic ion Ag+ (metal replaces metal ion)

• The silver becomes free silver and the nickel becomes the nickel (II) ion.

• Ni + AgNO3 Ag + Ni(NO3)2

–Balance the equation:

–Ni + 2AgNO3 2Ag + Ni(NO3)2

Thermite Reaction

• Steve Spangler Video Thermite

Thermite Reaction

• Al + Fe2O3

• Aluminum will replace iron (III) as was seen in the video.

• Iron (III) becomes Fe and aluminum metal becomes Al3+.

• 2Al + Fe2O3 Al2O3 + 2Fe

Double Replacement Reactions

Ions of two compounds exchange places with each other.

Reactants must be two ionic compounds, in aqueous solution

The general form is AX+BY = AY + BX

Remember the Demonstration!!!!!!!!

Word - Lead (II) Nitrate + Potassium Iodide --> Potassium Nitrate + Lead Iodide

Skeletal - Pb(NO3)2 (aq) + 2KI (aq) --> 2KNO3 (aq) + PbI2 (s)

What occurred???

This is a double displacement reaction

Double ReplacementNaOH + CuSO4 The Na+ and Cu2+ switch places.Na+ combines with SO4

2- to form Na2SO4.

Cu2+ combines with OH- to form Cu(OH)2

NaOH + CuSO4 Na2SO4 + Cu(OH)2

2NaOH + CuSO4 Na2SO4 + Cu(OH)2

Double Replacement

• CuSO4 + Na2CO3

• Cu2+ combines with CO32- to form

CuCO3.

• Na+ combines with SO42- to form

Na2SO4.

• CuSO4 + Na2CO3 CuCO3 + Na2SO4

Double Replacement Reactions

• Think about it like “foil”ing in algebra, first and last ions go together + inside ions go together

• Example: AgNO3(aq) + NaCl(s) AgCl(s) + NaNO3(aq)

• Another example:K2SO4(aq) + Ba(NO3)2(aq) KNO3(aq) + BaSO4(s)

2

Recognition

You need to be able to recognize which reaction is taking place

Practice Examples:• H2 + O2

• H2O

• Zn + H2SO4

• HgO

• KBr + Cl2

• AgNO3 + NaCl • Mg(OH)2 + H2SO3

Synthesis Decomposition Single Displacement Decomposition Single Displacement Double Replacement Double Replacement

Combustion Reactions• Combustion means “add Oxygen”

Normally, a compound composed of only C, H, (and maybe O) is reacted with oxygen – usually called “burning”

• If the combustion is complete, the products will be CO2 and H2O.

• If the combustion is incomplete, , the products will be CO (or possibly just C) and H2O.

Combustion ReactionWhen a substance combines with

oxygen, a combustion reaction results.The combustion reaction may also be an

example of an earlier type such as 2Mg + O2 2MgO.

The combustion reaction may be burning of a fuel.

Combustion Reactions• Combustion reactions involve

light and heat energy released.• Natural gas, propane, gasoline,

etc. are burned to produce heat energy.

• Most of these organic reactions produce water and carbon dioxide.

Combustion ReactionWhen hydrocarbon compounds CxHx are

burned in oxygen, the products are water and carbon dioxide.

CH4 + O2 CO2 + H2O

CH4 + 2O2 CO2 + 2H2O

Demonstration

Combustion Reactions

Generally combustion reactions involve the burning of a Hydrocarbon (CxHx) in Oxygen.

Other elements can also burn with Oxygen2Mg + O2 2MgO+ Energy

2H2 + O2 2H2O+ Energy (basis behind fuel cell energy)

P4 + 5O2 P4O10 + Energy (matches)

PracticeClassify each of the following as to type:

H2 + Cl2 2HClSynthesis

Ca + 2H2O Ca(OH)2 + H2

Single Displacement

Practice2CO + O2 2CO2

Synthesis and Combustion

2KClO3 2KCl + 3O2

Decomposition

PracticeFeS + 2HCl FeCl2 + H2S

Double Replacement

Zn + 2HCl ? ZnCl2+ H2

Single Displacement