The Foundations of Chemistry

(Marcin) #1

Millions of compounds are known, so
it is important to be able to associate
names and formulas in a systematic
way.


160 CHAPTER 4: Some Types of Chemical Reactions


SUMMARY OF REACTION TYPES


Table 4-14 summarizes the reaction types we have presented. Remember that a reaction
might be classified in more than one category.

EXAMPLE 4-14 Classifying Reactions
Classify each of the following reactions.
(a) Zn(s)AgNO 3 (aq)88nZn(NO 3 ) 2 (aq)2Ag(s)
heat
(b) Ca(OH) 2 (s)888nCaO(s)H 2 O(g)
heat
(c) 2HI(g)888nH 2 (g)I 2 (g)
(d) Cu(NO 3 ) 2 (aq)Na 2 S(aq)88nCuS(s)2NaNO 3 (aq)
(e) SO 2 (g)H 2 O()88nH 2 SO 3 (aq)
(f ) H 2 SO 3 (aq)2KOH(aq)88nK 2 SO 3 (aq)2H 2 O()

Plan
We identify each reaction type by its characteristics, using Table 4-13 and the appropriate
sections as a guide.
Solution
(a) One element, Zn, displaces another, Ag, from a compound; this is a displacement reac-
tion.
(b) A single compound breaks apart into two compounds; this is a decomposition reaction.
(c) A single compound breaks apart into two elements; this is another decomposition reac-
tion.
However, now there are changes in oxidation numbers; H changes from 1 in HI
to 0 in H 2 , and I changes from 1 in HI to 0 in I 2. So this is also an oxidation-
reduction (redox) reaction.
(d) The positive and negative ions in the two reactant compounds change partners; this is a
metathesis reaction. An insoluble product, CuS(s), is formed, so the reaction is a precip-
itation reaction.
(e) Two compounds combine to form a single product; this is a combination reaction.
(f ) The positive and negative ions change partners; this is a metathesis reaction. An acid and
a base react to form a salt and water; this is an acid-base (neutralization) reaction.

You should now work Exercises 93 through 101.

NAMING INORGANIC COMPOUNDS


The rules for naming inorganic compounds are set down by the Committee on Inorganic
Nomenclature of the International Union of Pure and Applied Chemistry (IUPAC). The
names and formulas of a few organic compounds were given in Table 2-2, and more
systematic rules for naming them will appear in Chapter 27.

4-10

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