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Solving Problems: A Chemistry Handbook
Chemistry: Matter and Change
85
SOLVING PROBLEMS:
A CHEMISTRY HANDBOOK
CHAPTER 9
Practice Problems
3. Identify each of the following skeleton equations as representing a synthesis reaction, a combustion reaction, both synthesis
and combustion, or decomposition reaction. Balance each
equation if necessary.
a. N 2 (g) ϩ H 2 (g) 0 NH 3 (g)
b. CaCO 3 (s) 0 CaO(s) ϩ O 2 (g)
c. Se(s) ϩ O 2 (g) 0 SeO 3 (g)
d. C 2 H 4 (g) ϩ O 2 (g) 0 CO 2 (g) ϩ H 2 O(g)
Replacement reactions In a single-replacement reaction,
atoms of an element replace the atoms of another element in a compound. An example of such a reaction is the replacement by zinc
metal of silver in silver nitrate water solution.
Zn(s) ϩ 2AgNO 3 (aq) 0 Zn(NO 3 ) 2 (aq) ϩ 2Ag(s)
Not all metals will replace one another. Only a metal that is more
reactive chemically will replace a chemically less reactive metal.
The order of such reactivity is called an activity series, as shown
below.
Any metal in an activity series will replace the metals below it in
their compounds. In a similar fashion, any elemental halogen will
replace another halogen from its compounds if the second halogen
lies below it in the periodic table. Thus, fluorine is more active than
chlorine, which is more active than bromine, which is more active
than iodine.
Lithium
Potassium
Sodium
Magnesium
Aluminum
Zinc
Iron
Lead
Copper
Silver
Most active
Least active
Example Activity Series
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