Single & Double Replacement & Combustion Packet
Name________________________________
ChemCom: Materials Unit C
Period_______Date_____________________
In a Single Replacement Reaction a free element takes the place of or replaces another element that is part
of a compound. The element that was replaced is now “free.”
A
+
free element
BC
→
compound
AC
+
new compound
B
new free element
Let’s study an actual replacement reaction – one between zinc (Zn) and hydrochloric acid (HCl). The
zinc is the “free” element and the hydrochloric acid is the compound.
Zn
+
HCl
→
ZnCl2
+
The zinc replaces the hydrogen.
H2
The hydrogen gas is set free.
The reaction produces a new compound, zinc chloride (ZnCl2), and free hydrogen (H2). Notice
that the elements we started with are the elements we ended with, they are just arranged in a different
way. This kind of reaction is called a single replacement reaction where a free element replaces an
element that is part of a compound.
For example, if you do a simple experiment of placing an iron nail (Fe) in a solution of copper (II)
sulfate (CuSO4), you will see that after a few minutes the nail is coated with copper metal. Here is the
equation for the reaction:
Fe
+
CuSO4
→
FeSO4
+
Cu
1. Name the free element the reaction starts with:
_______________________________
2. Name the compound the reaction starts with:
_______________________________
3. Name the free element the reaction ends with:
_______________________________
4. Name the compound the reaction ends with:
_______________________________
5. Which element did the iron replace?
_______________________________
6. What happened to that element? _____________________________________________
7. What do we call this kind of reaction?
_______________________________
8. What happens during a single replacement reaction? ________________________________________
___________________________________________________________________________________
1
Identify (√) the following reactions as
Synthesis (Syn), Decomposition (Decomp),
Single Replacement (SR) or None of These
Synthesis
Reaction
Equation
1.
C + 2S → CS2
2.
2H2O2 → 2H2 + O2
3.
2Al + 6HCl → 2AlCl3 + 3H2
4.
Li3PO4 + 3NaF → 3LiF + Na3PO4
5.
Zn + PbO → ZnO + Pb
6.
CuCl2 + 2KBr → CuBr2 + 2KCl
7.
CuSO4 + Fe → Cu + FeSO4
8.
2Na + Br2 → 2NaBr
9.
2HgO → 2Hg + O2
10.
C3H8 + 5O2 → 3CO2 + 4H2O
Decomposition
Reaction
Single
Replacement
Reaction
None of
These
Double Replacement Reactions:
A double replacement reaction takes place between two compounds. A part of one compound
changes place with a part of the other compound. This produces two new compounds.
AB
+
compound
CD
→
compound
AD
+
new compound
CB
new compound
The positive ion of one compound switches place with the positive part of the other compound. Let’s
look at an example of a double replacement reaction between sodium hydroxide and hydrochloric acid:
NaOH
+
HCl
→
NaCl
+
HOH
The sodium and hydrogen change places and two new compounds form, NaCl and HOH (water).
Example #1) BaCl2
barium
chloride
+
Na2SO4
sodium
sulfate
→
BaSO4
barium
sulfate
+
2NaCl
sodium
chloride
1. Name the reactants: ______________________________ __________________________________
2. The reactants are: all elements / all compounds / an element and a compound (circle one.)
2
3. The barium changed places with the sulfate / chlorine / sodium (circle one).
4. Name the products: ______________________________ ___________________________________
5. The products are: all elements / all compounds / an element and a compound (circle one.)
6. What kind of chemical reaction is this? ___________________________________________________
7. Double replacement is the reaction of two __________________ to form two new ________________.
Example #2) AgNO3
silver
nitrate
+
NaBr
→
AgBr
sodium
bromide
+
silver
bromide
NaNO3
sodium
nitrate
8. Name the reactants: ______________________________ __________________________________
9. The reactants are: all elements / all compounds / an element and a compound (circle one.)
10. The silver changed places with the sodium / bromine / nitrate (circle one).
11. Name the products: ______________________________ ___________________________________
12. The products are: all elements / all compounds / an element and a compound (circle one.)
13. What kind of chemical reaction is this? __________________________________________________
Identifying Double Replacement Reactions:
Equation
1.
Mg(OH)2 + 2HCl → MgCl2 + 2H2O
2.
C6H10O5 +H2O → C6H12O6
3.
Na2SO4 + BaCl2 → 2NaCl + BaSO4
4.
3Mg + N2 → Mg3N2
5.
H2SO4 + BaCl2 → 2HCl + BaSO4
6.
CH4 + 2O2 → CO2 + 2H2O
7.
ZnCO3 → ZnO + CO2
8.
CuSO4 + H2S → H2SO4 + CuS
9.
NH4NO3 → 2H2O + N2O
10.
C6H12 + 9O2 → 6CO2 + 6H2O
A Double
Replacement
Reaction
Not a Double
Replacement
Reaction
3
Identify (√) the following reactions as
Synthesis (Syn)
Decomposition (Decomp)
Single Replacement (SR)
Double Replacement (DR)
Other
Equation
Reaction Type
Syn.
1.
N2 + 3H2 → 2NH3
2.
2Br2 + 2H2O → 4HBr + O2
3.
Mg + 2HCl → MgCl2 + H2
4.
2KBr + H2SO4 → K2SO4 + 2HBr
5.
H2SO3 → H2O + SO2
6.
C6H12O6 + 6O2 → 6CO2 + 6H2O
7.
NaCl + AgNO3 → NaNO3 + AgCl
8.
H2 + Cl2 → 2HCl
9.
H2CO3 → H2O + CO2
10.
C3H8 + 5O2 → 3CO2 + 4H2O
Decomp.
S.R.
D.R.
Other
Combustion Reactions:
A combustion reaction takes place between a hydrocarbon (a compound made of hydrogen and
carbon) and the element oxygen. Oxygen is a diatomic element which means it is so reactive it will bond
with itself. Therefore the oxygen in the air required for combustion is O2. Carbon dioxide and water are
always the products for these types of reactions.
CH
+
hydrocarbon
O2
→
oxygen
CO2
+
carbon dioxide
H2 O
water
For example, when natural gas (methane, CH4) is burned with oxygen (O2) carbon dioxide (CO2) and
water (H2O) are produced.
CH4
+
methane
2O2
→
oxygen
CO2
+
carbon dioxide
2H2O
water
In another example, cellular respiration, our body metabolizes glucose (C6H12O6) with oxygen (O2) and
we produce carbon dioxide (CO2) and water (H2O). In this case the “hydrocarbon” also contains oxygen.
C6H12O6
glucose
+
6O2
oxygen
→
6CO2
carbon dioxide
+
6H2O
water
4
1. Name the type of compound combustion reactions start with: _________________________________
2. What elements make up a hydrocarbon? ______________________ & ______________________
3. What element is needed for a combustion reaction to occur? ______________________________
4. Where does this element come from? ______________________
5. Because oxygen is so reactive, it is never found alone in nature. It is a ___________________element.
6. When we write oxygen in a chemical reaction it is always written ________.
7. Name the reactants: ___________________________(general term) & _________________________
8. The reactants are: both compounds / both elements / always include a hydrocarbon (HC) & oxygen
9. When the hydrocarbon and oxygen react they always form 2 products: _________________________
_________________________
10. The products are: both elements / water / carbon dioxide / carbon dioxide & water (circle one.)
11. Reactions of hydrocarbons and oxygen always form carbon dioxide and water, this is called a
___________________________ reaction.
12. Combustion reactions always involve reacting a _____________________________ with oxygen to
produce ___________________________ and __________________________.
Equation
1.
Mg(OH)2 + 2HCl → MgCl2 + 2H2O
2.
2Br2 + 2H2O → 4HBr + O2
3.
C3H8 + 5O2 → 3CO2 + 4H2O
4.
3Mg + N2 → Mg3N2
5.
H2SO4 + BaCl2 → 2HCl + BaSO4
6.
CH4 + 2O2 → CO2 + 2H2O
7.
ZnCO3 → ZnO + CO2
8.
C6H10O5 +H2O → C6H12O6
9.
NH4NO3 → 2H2O + N2O
10.
C6H12 + 9O2 → 6CO2 + 6H2O
A Combustion
Reaction
Not a
Combustion
Reaction
5
Identify (√) the following reactions as
Synthesis (Syn)
Decomposition (Decomp)
Single Replacement (SR)
Double Replacement (DR)
Combustion (C)
Reaction Type
Equation
Syn.
1.
CO2 → C + O2
2.
NaCl + AgNO3 → NaNO3 + AgCl
3.
S + Cl2 → SCl2
4.
BaCl2 + 2NaOH → 2NaCl + Ba(OH)2
5.
C3H8 + 5O2 → 3CO2 + 4H2O
6.
CH4 → C + 2H2
7.
Pb(NO3)2 + Mg → Pb + Mg(NO3)2
8.
Mg + 2HCl → MgCl2 + H2
9.
H2SO4 → H2 + S + 2O2
10.
2O2 + N2 → N2O4
11.
3CaBr2 + 2Na3P → Ca3P2 + 6NaBr
12.
2KI + Br2 → 2KBr + I2
13.
C6H12O6 → 6C + 6H2O
14.
C6H12 + 9O2 → 6CO2 + 6H2O
15.
Si + O2 → SiO2
16.
2NaI + Pb(NO3)2 → 2NaNO3 + PbI2
17.
2C8H18 + 25O2 → 16CO2 + 18H2O
18.
H2 + CO + O2 → H2CO3
19.
C6H12O6 + 6O2 → 6CO2 + 6H2O
20.
CS2 + 2F2 → CF4 + 2S
Decomp.
S.R.
D.R.
C
6