Types of Chemical
Reactions
Types of Chemical Reactions
Be able to
1) determine products when given reactants and
type of reaction
2) name what type of reaction has occurred when
given reactants and products
3) predict what type of reaction will occur when
given reactants
4) predict what, if any, replacement reactions will
occur when given reactants, a Table of
Solubilities, and an Activity Series Table
Types of Chemical Reactions
1. Combination Rx
a.k.a.
Synthesis Rx
2. Decomposition Rx
a.k.a.
Analysis Rx
3. Single Exchange Rx
a.k.a.
Single Replacement Rx
Single Displacement Rx
Single Substitution Rx
4. Double Exchange Rx
a.k.a.
Double Replacement Rx
Double Displacement Rx
Double Substitution Rx
5. Combustion Rx
(Single Exchange)
(Double Exchange)
Watch These Reactions!
Combination Reactions
• a chemical change in which two or more
substances react to form a single new
substance
• the general form is A + X  AX
– 2Cu(s) + S(s)  Cu2S(s)
– 2Fe(s) + 3S(s)  Fe2S3(s)
– K(s) + Cl2(g)  ?
• ions are: K+1 and Cl-1
• therefore: K(s) + Cl2(g)  KCl(s)
• balanced: 2K(s) + Cl2(g)  2KCl(s)
Combination Reactions
Combination Reactions
Practice (combination reactions)
Complete and balance these equations
(hint: consider how many valence electrons each atom has):
1. Sodium metal reacts with chlorine gas
Na + Cl2 
2. Solid Magnesium reacts with fluorine gas
Mg + F2 
3. Aluminum metal reacts with fluorine gas
Al + F2 
Practice (combination reactions)
Predict products and balance equations
(hint: consider how many valence electrons each atom has):
1. Sodium metal reacts with chlorine gas
Na + Cl2  NaCl
(unbalanced)
2Na + Cl2  2NaCl (balanced)
2. Solid Magnesium reacts with fluorine gas
Mg + F2  MgF2 (balanced)
3. Aluminum metal reacts with fluorine gas
Al + F2  AlF3 (unbalanced)
2Al + 3F2  2AlF3 (balanced)
Decomposition Reactions
• a single compound breaks down into two or
more products
• AX  A + X
– 2HgO(s) → 2Hg(l) + O2(g)
– Zn(ClO3)2  ZnCl2 + 3O2
– H2O(l) electricity
→ ?
electricity
• H2O(l)
→
H2(g) + O2(g)
electricity
• 2H2O(l)
→ 2H2(g) + O2(g)
Decomposition of H2O (hydrolysis)
2H2O(l) → 2H2(g) + O2(g)
(H2)
(O2)
(electrode with
neg. charge)
(electrode with
pos. charge)
Electrical current
splits H2O molecules
Decomposition Reactions
Practice (Decomposition Rx’s)
Predict the products. Write and balance
the reaction equations:
1. Solid Lead (IV) oxide decomposes
– Pb is 4+ and O is 2- therefore…
• PbO2  Pb + O2
2. Aluminum nitride decomposes
– Al is 3+ and N is 3- therefore…
• AlN  Al + N2
Single Replacement Reactions
• a chemical change in which one element
replaces a second element in a compound
– metal+ will replace a metal +, or a
nonmetal - will replace a nonmetal – general form is A + BX  B + AX
Example: zinc metal reacts with
aqueous hydrochloric acid
Zn (s) + 2HCl (aq)  ZnCl2 (aq) + H2 (g)
Single Replacement Reactions
Single Replacement Reactions
Single Replacement Reactions
• Use “Activity Series” table to determine
which elements will replace others to
complete a replacement reaction.
• “Highly active” elements will replace less
“active” elements
Single Replacement Reactions
Single Replacement Reactions
– Ni + AgNO3  ?
• both Ni and Ag are positive ions (cations)
• see the activity series table to see which
is the most reactive
– since nickel is… silver becomes free silver
and the nickel becomes the nickel(II) ion
(Ni+2) and will replace the silver
• NO3 is 1• Ni + AgNO3  Ag + Ni(NO3)2
–balance the equation:
–Ni + 2AgNO3  2Ag + Ni(NO3) 2
Single Replacement Reactions
• aluminum metal reacts with aqueous copper (II)
nitrate
– Al is a metal / Cu is 2+ and NO3 is 1– Al(s) + Cu(NO3)2(aq) ?
– Al is higher on the reactivity table and will
replace Cu
– the new product is a result of the new Al 3+
and NO3 1- ions bonding
– Al(s) + Cu(NO3)2(aq) Cu(s) + Al(NO3)3(s)
– 2Al(s) + 3Cu(NO3)2(aq) 3Cu(s) + 2Al(NO3)3(s)
Single Replacement Reactions
• Al + Fe2O3  ?
– O is 2- and therefore Fe was 3+
– aluminum will replace iron(III)
– iron(III) becomes simply Fe, and aluminum
metal becomes Al3+
– Al + Fe2O3  Fe + Al2O3
– 2Al + Fe2O3  2Fe + Al2O3
Double Replacement Reactions
• Assume the following double
replacement reaction will take place:
– Na2CO3 + HCl  ?
– Na+1 combines with Cl-1 to form NaCl
– H+ combines with CO32- to form H2CO3
– Na2CO3 + 2HCl  2NaCl + H2CO3
Double Replacement Reactions
an exchange of positive ions between two
chemicals
– a reaction will occur if any of the following
will be products:
• a precipitate (see solubility table/cheat sheet)
(precipitate = solid produced in a chemical reaction)
• a gas
• water
• general form is AX + BY  BX + AY
Example: CuSO4 + Na2CO3  Na2SO4 + CuCO3
Double Replacement Reactions
• NaOH + CuSO4  ?
– Will either new product form a precipitate?
– Look at Table of Solubilities in Water to determine
this. If so, this indicates a reaction will take place.
– Answer: Yes, copper (Cu) and hydroxide (OH) will
form a precipitate according to the table.
– Therefore, the Na+ and Cu2+ will switch places
• Na+ combines with SO42- to form Na2SO4.
• Cu2+ combines with OH- to form Cu(OH)2
• NaOH + CuSO4  Na2SO4 + Cu(OH)2 (unbalanced)
• 2NaOH + CuSO4  Na2SO4 + Cu(OH)2 (balanced)
Combustion Reaction
• a type of combination reaction where a
substance reacts with oxygen
• often produces carbon dioxide
water
light
heat
Combustion Reaction
• CH4 + O2  ?
• CH4 + O2  CO2 + H2O
• CH4 + 2O2  CO2 + 2H2O
Practice – Types of Rx’s
• Which type of reaction are the following?
• H2 + Cl2  2HCl
• Ca + 2H2O  Ca(OH)2 + H2
Practice – Types of Rx’s
• Which type of reaction are the following?
• H2 + Cl2  2HCl
– combination
• Ca + 2H2O  Ca(OH)2 + H2
Practice – Types of Rx’s
• Which type of reaction are the following?
• H2 + Cl2  2HCl
– combination
• Ca + 2H2O  Ca(OH)2 + H2
– single replacement
Practice – Types of Rx’s
• 2CO + O2  2CO2
• 2KClO3  2KCl + 3O2
Practice – Types of Rx’s
• 2CO + O2  2CO2
– combination
• 2KClO3  2KCl + 3O2
Practice – Types of Rx’s
• 2CO + O2  2CO2
– combination
• 2KClO3  2KCl + 3O2
– decomposition
Practice – Types of Rx’s
• FeS + 2HCl  FeCl2 + H2S
• Zn + HCl  ?
Practice – Types of Rx’s
• FeS + 2HCl  FeCl2 + H2S
– double replacement
• Zn + HCl  ?
Practice – Types of Rx’s
• FeS + 2HCl  FeCl2 + H2S
– double replacement
• Zn + HCl  ?
– Zn + 2HCl  ZnCl2 + H2
Practice – Types of Rx’s
• FeS + 2HCl  FeCl2 + H2S
– double replacement
• Zn + HCl  ?
– Zn + 2HCl  ZnCl2 + H2
– single replacement