A1261837809xAeHL

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USING OXIDATION NUMBERS
The three major uses for oxidation numbers
are 1 determining whether or not oxidation and
reduction are involved in a chemical reaction (as
just explained) 2 naming compounds in a
systematic way 3 balancing diffi cult chemical
equations.
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The concept of oxidation numbers (states) allows
us to extend this technique to naming anions.
Rather than using terms such as hypochlorite,
chlorite, chlorate, perchlorate, manganate or
permanganate, which alone do not tell us the
formula of the anion, we can now name all
oxyanions as -ates and put the oxidation
state (number) in brackets after it chlorate(I),
chlorate(III), chlorate(V), chlorate(VII), mangana
te(VI) and manganate(VII) for the ions just
named. These names tell us the formulae of the
anions chlorate(I) must be ClO, chlorate(III),
ClO2 , chlorate(V), ClO3 , manganate(VII),
MnO4 and so on. Unfortunately this systematic
naming of anions is less widely used than that
for cations hypochlorite and permanganate, for
example, are much more commonly used. When
discussing the chemistry of various elements we
often talk in terms of their oxidation states in
order to avoid ambiguity. We refer to iron in the
2 or 3 state, chlorine in the 1,3,5, or 7
states or manganese in the 2, 3, 4, 6, or 7
states, even if we are still using names such as
hypochlorite or permanganate.
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EXERCISES
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BALANCING REDOX REACTIONS
Ignore this method its difficult
Balancing using half reactions from a table
I would use this
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higher
lower
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C O2
CO2
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2e-
Cl2
2Cl-

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