Six Types of ReactionsSix Types of Reactions

• SynthesisSynthesis• DecompositionDecomposition• Single ReplacementSingle Replacement• Double ReplacementDouble Replacement• CombustionCombustion• Acid-Base Acid-Base (We will talk about this (We will talk about this

later.)later.)

Synthesis reactionsSynthesis reactions• Two substances combine and form one Two substances combine and form one

compound.compound. • Form: A + B Form: A + B AB AB• Explosion of the HindenburgExplosion of the Hindenburg• Example: 2HExample: 2H2 2 + O+ O2 2 2H 2H22OO

Synthesis ReactionsSynthesis Reactions

Decomposition ReactionsDecomposition Reactions• One compound breaks down into two or

more substances• Form: AB A + B• Example: 2H2O → 2H2 + O2

DecompositionDecomposition• Car air bags

- Sodium azide is electrically stimluated to decompose into nitrogen gas and sodium nitrate

2NaN3 → Na3N + 4N2

• Many decomposition Many decomposition reactions involve the reactions involve the fast release of large fast release of large quantities of energy.quantities of energy.

Decomposition ReactionsDecomposition Reactions

Single Replacement ReactionsSingle Replacement Reactions

• One element replaces One element replaces another in a another in a compound.compound.

• Form: Form: A + BC A + BC AC + AC + B B

• Example: Example: Mg + 2HMg + 2H22O O →→ Mg(OH) Mg(OH)22 + +

HH22

Single Replacement ReactionsSingle Replacement Reactions

Double Replacement ReactionsDouble Replacement Reactions• Two elements switch places to form 2 Two elements switch places to form 2

new compoundsnew compounds• Form: AB + CD Form: AB + CD AD + CB AD + CB

• Ex: HCl + NaOH Ex: HCl + NaOH NaCl + H NaCl + H22OO

Combustion ReactionsCombustion Reactions

• OxygenOxygen reacts with another element reacts with another element to make water and COto make water and CO22..

• Releases energy as heat and light.Releases energy as heat and light.• Some combustion reactions can be Some combustion reactions can be

synthesis reactions.synthesis reactions.

Combustion ReactionsCombustion Reactions• Form:

X + O2 CO2 + H2O

• C10H8 + 12O2 10CO2+ 4H20

Combustion is used to heat homes and run automobiles (octane, as in gasoline, is C8H18)

SynthesisSynthesisDecompositionDecompositionSingle replacementSingle replacementDouble replacementDouble replacement_______ Pb(NO_______ Pb(NO33))2 2 + 2NaI → PbI+ 2NaI → PbI22+ 2Na(NO+ 2Na(NO3 3 ))_______NH_______NH33 + H + H22O → (NHO → (NH44)(OH))(OH)_______CaF_______CaF22 + H + H22(SO(SO44) → Ca(SO) → Ca(SO44) + 2 HF) + 2 HF_______N_______N22 + 3H + 3H22 → 2NH → 2NH33

_______MgI_______MgI22 + Br + Br22 → MgBr → MgBr22 + I + I22

_______2H_______2H22O → 2HO → 2H22 + O + O22

_______C_______C44HH10 10 + O2 -> CO2 + H2O

What type of Reaction?What type of Reaction?