Transcript Types of Chemical Reactions

Types of Chemical Reactions
Learning Target: To be able to identify the different
type of reactions when looking at skeletal equations
Types of Reactions:
 There
1.
2.
3.
4.
5.
are 5 types of Reactions:
Synthesis
Decomposition
Single-replacement
Double-replacement
Combustion
Synthesis:
A chemical rxn in which 2 or more
substances (A + B) react to produce a single product (AB)
A + B ⇒ AB
Na(s) + Cl2(g) ⇒ NaCl(s)
SO2(g) + O2(g) ⇒ SO3(g)

You can spot a synthesis reaction because there is only 1
product.
Decomposition:
A rxn in which a single compound (AB)
breaks down into 2 or more new substances (A + B…)
AB ⇒ A + B
NH4NO3(s) ⇒ N2O(g) + H2O(g)
Na3N(s) ⇒ Na(s) + N2(g)
 You
can identify a decomposition rxn because there
is only one reactant.
Single Replacement: A rxn in which the atoms of one
element replace the atoms of another element in a compound
A + BX ⇒ AX + B
Li(s) + H2O(l) ⇒ LiOH(aq) + H2(g)
Cu(s) + AgNO3(aq) ⇒ Ag(s) + Cu(NO3)2



In single replacement the metal with the higher activity will replace the
metal with the lower activity.
You can spot a single replacement reaction by the single element on each
side of the equation.
Think of your friend stealing your boyfriend/girlfriend from you, and you
are left by yourself.
Activity Series: Single Replacement Rxn

Active metals will replace less
active metals in reactions.
Pt(s) + Zn2O (aq) → NR
Fe(s) + CuSO4(aq) →
FeSO4(aq) + Cu(s)
Na(s) + SnCO3(aq) →
Na2CO3(aq) + Sn(s)
Double Replacement: a rxn which involves an
exchange of ions between 2 compounds
AX + BY ⇒ AY + BX
*Either the metals change places or the nonmetals change places but
not both!!!
Ca(OH)2(aq) + HCl(aq) ⇒ CaCl2(aq) + H2O(l)
*Typically occurs in aqueous solutions (in water)
NaOH(aq) + CuCl2(aq) ⇒ NaCl(aq) + Cu(OH)2(s)
*Precipitate: Is when a solid forms from a solution
 You can identify double replacement by the two compounds on
each side of the equation.
3 Types of Double Replacement:
1.
Formation of a precipitate
2.
Formation of H2O
3.
Formation of a product which
decomposes into a gas
Double-Replacement: Formation of a
precipitate

Solubility Rules:


Some compounds will dissolve in water (soluble)
Some will NOT dissolve in water (insoluble/ not soluble)

If during a double-replacement rxn, a solid is formed, it will fall
out of the solution. This is called a percipitant.

Ex: Cd(SO4)(aq) + K2S(aq)
CdS(s) + K2 (SO4)(aq)
Double-Replacement: Formation of H2O
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These occur between Acids and Bases
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
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Acids ALWAYS start with _________
Bases are compounds that end with hydroxides (OH-)
One product will be H2O and one will be an ionic salt
compound
HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)
*Some people consider this a separate rxn altogether
Combustion: a rxn in which O2 can combine
with a substance to release energy

Ex: Fire, Burning, etc.
C(s) + O2(g) ⇒ CO2(g)
CH4(g) + O2(g) ⇒ CO2(g) + H2O(l)
*In most cases, the products will be H2O and CO2
Practice Problems: Complete these in your notes, I
will call students up to share their answers.
1.
_________________________C2H6(g) + O2(g) → H2O(g) +CO2(g)
2.
_________________________ Br2(l) + LiI(s) → LiBr + I2(s)
3.
_________________________ Fe(s) + H2O(l) →Fe3O4(s) + H2(g)
4.
_________________________ MgCO3(s) → MgO(s) + CO2(g)
5.
_________________________ P4(s) + O2(g) → P4O10(s)
6.
_________________________ KNO3(s) → KNO2(s) + O2(g)
7.
_________________________ KOH + H3PO4 →K3PO4 + H2O
8.
_________________________ Na(s) + O2(g) →Na2O(s)
9.
_________________________ O2(g) + C6H12O6(g) → H2O(g) + CO2(g)