Chemical reactions

1. 8
th
Grade Science

2. Type of
Reaction
Definition  Equation
Synthesis
Decomposition
Single
Replacement
Double
Replacement
Watch the movie and then complete the chart.
A = Red B = Blue C = Green D = Yellow
A + B → AB
AB → A + B
AB + C → AC + B
AB + CD → AC +
BD
Two or more elements or
compounds combine to
make a more complex
substance
Compounds break down
into simpler substances
Occurs when one element
replaces another one in a
compound
Occurs when different
atoms in two different
compounds trade places
Chemical
Reactions

3. Identifying Chemical Reactions
____ P + O
2
→ P
4
O
10
____ Mg + O
2
→ MgO
____ HgO → Hg +
O
2 ____ Al
2O
3 → Al + O
2
____ Cl
2
+ NaBr → NaCl + Br
2
____ H
2
+ N
2
→ NH
3
2. Use colored pencils to circle the common atoms or compounds in each equation to
help you determine the type of reaction it illustrates. Use the code below to classify
each reaction.
S = Synthesis D = Decomposition SR = Single Replacement DR = Double Replacement

4. ____ Na + Br
2
→ NaBr ____ CuCl
2
+ H
2
S → CuS + HCl

____ HgO + Cl
2
→ HgCl + O
2
____ C + H
2
→ CH
4

____ KClO
3
→ KCl + O
2
____ S
8
+ F
2
→ SF
6

____ BaCl
2
+ Na
2
SO
4
→ NaCl + BaSO
4