Name ____________
Date _ _ _ _ _ _ __
Class _ _ _ _ _ __
OXIDATION NUMBERS
l··· · · · ·
Section Rt!view
Part A Completion
Use this completion exercise to check your understanding ofthe concepts and terms that are introduced in this section. Each blank can be completed with a term, short phrase, or number. The oxidation number of an element in an uncombined state
is
1
. The oxidation number of a monatomic ion is the same
in magnitude and _=2_ as its ionic
3
. The sum of the
oxidation numbers of the elements in a neutral compound is
1. 2. ._ _~~_ _ _ _ __ 3. 4. 4
. In a polyatomic ion, however, the sum is equal to the
5.
5
. Oxidation numbers help you keep track of
6.
6
transfer in redox reactions. An oxidation number increase is
7
, while a _....:8,,--_ is reduction.
7. 8. Match the oxidation number of nitrogen in each formula in Column B to the correct oxidation number in Column A Column A
Column B
The.
~0
17. - 3
a. N2
18. -2
h. HN0 3
~ ~u.J ~
19. -1
c. NO
~em~i
20. 0
d. NH 20H
21. +1
e. NH3
22. +2
f. N 20 3
23. +3
g. N 20
24. +4
h. N2H4
25. +5
i. N0 2
& t-V
rwr.J
I!>
0
XI d J.,'
t)
11...
~W.sl
€
., .
, !
'/"j
Nrune ______________________
Date _________ -Class _ _ _ _ _ __
OXIDATION-REDUCTION REACTIONS ,
Practice Problems
In your notebook, solve the following problems.
SECTION 20.1 THE MEANING OF OXIDATION AND REDUCTION
Determine what is oxidized and what is redu Ced in each reaction Identify the
oxidizing agent and the reducing agen t.
R. eelu t-e cI.
eX-td/~ed
1. 2Sr + Oz ~ 2SrO
ifJ eK-#::
2. 2Li + S ~ 2Li zS
3. 2Cs + Brz ~ 2CsBr
2NaBr~
2NaCl + Br2
. ..'- - - . . ,
-~
9. Mg + 2HCl ~ MgCl 2 + Hz
~
_M
, _ v.:.::.~~,p ~
-
7. Si + 2Fz ~ Sif 4
8. 2Ca + O2 ~ 2CaO
10. 2Na + 2H 20
Ajelf.
~.:.f-;;;'
4. 3Mg + Nz ~ Mg3Nz
5. 4Fe + 30 2 ~ 2Fez03
6. Cl 2 +
lleduc/~
OJ'!/d/2.i:.;
I
2NaOH + H2
,
:":~
_Y."IC:IoI~~~_""'
t
-
- '
.........
.'\f
"
'
~""C'I_ .." ' "
SECTION 20.2 OXIDATION NUMBERS
1. Give the oxidation number of each kind of atom or ion.
a. Sn
c. Sz­
h. K+
d. Fe3 +
e. Se
2. Calculate the oxidation number of chromium in each of the following formulas.
a. Cr203
(jl
h. HzCrz0 7
c. CrS0 4
d. CrO/­
Use the changes in oxidation number to determine which elements are oxidized
and which are reduced in these reactions. (Note: It is not necessary to use
balanced reactions.)
a. C + HzS0 4 ~ CO z + SOz + HzO
h. HN03 + HI~ NO + 12 + HzO
c. KMn0 4 + HCl ~ MnClz + Cl2 + HzO + KCl
@
;.'
___ ~~"-'_'fh6
~---.-
d. Sb + HN03 ~ Sb 20 s + NO + H20
For each reaction in problem 3 above, identify the oxidizing agent and reducing
agent.
Chapter 20 Oxidation-Reduction Reactions
...
523
Name ____________
Date
_~
Oass _ _ _ _ _ __
_ _ _ _ __
OXIDATION NUMBERS
Section Review Part A Completion Use this completion exercise to check your understanding of the concepts and tenns that are introduced in this section. Each blank can be completed with a term, short phrase, or number. - ,. The oxidation number of an element in an uncombined state
is
1
. The oxidation number of a monatomic ion is the same
in magnitude and
2
as its ionic
3
. The sum of the
oxidation numbers of the elements in a neutral compound is
-zerO
1.
(Sisn)
ChG\r~e
2• .
3.
c,h~(~e
4.
-z.e( 0
c.. h Oof ~ eo.
0
f the. po\'1 G\.fom.\ C
4
. In a polyatomic ion, however, the sum is equal to the .
5. 5
. Oxidation numbers help you keep track of
6.
eleCTro(\
7. o Xido.tion
6
transfer in redox reactions. An oxidation number increase is
7
, while a
8
is reduction. Match the oxidation number ofnitrogen in eachformula in Column B to the correct
oxidation number in Column A
Column A e
h
Column B
Ihf~0
purt~e
4e¥"<=-f.5 .e
17. -3
a. N2
18. -2
b. HN0 3
1:0
19. -1
c. NO
'f.J.emeJCI.
20. 0 d. NH20H
cr
21. +1 e. NH3 C
22. +2
f.
f
23. +3
g. N20
24. +4 h. N2H4 25. +5
L N0 2
d
a
b
N20 3 ~u.) ~
of
If:>
c(1....-­
c.Jl.Yt At:t.ve d Af·,. tf)1'l
&e-II~ ()xi
~U".sl
ff" @
.."
'"
Q
l2! ­
Nrune ______________________
Date _____________
- C1~s
______________
OXIDATION-REDUCTION REACTIONS
Practice Problems
In your notebook, solve the following problems_
SECTION 20.1 THE MEANING OF OXIDATION AND REDUCTION
Determine what is oxidized and what is reduced'm each reaction Identify the
.'
oxidizing agent and the reducing agen t
.£edu. i-e.c {
2SrO ~
1. 2Sr + O2 -
2. 2Li + S - 2Li2S
3. 2Cs
. G;udned
.
.
"2.
+ Br2 - 2CsBr
4. 3Mg + N2 - Mg3N 2
.-
+ 30 2 - 2Fe 20 3
6. C12 + 2NaBr - 2NaCl + Br2
5. 4Fe
+ 2F2 - SiF4 8. 2Ca + O2 - 2CaO
9. Mg + 2HCl- MgC12 + Hz
7. Si
10. 2Na
+ 2H 20 - 2NaOH + H2
kduc7.J
Sf
L',
AJ~I(
ifJelt-l:
Sr
L'.
02­
O;z.
S
C;
Cs
Br
Be­
es
Mg
fe
N2.
i'h.
M.9
0,
01.
~e
el2.
CI-a.
Be-I
,.
5
Bt'"
·1
, -..-... ~ou.-:':"'O _",
F
02­
Si
1-
~.~--
CQ
8.
q.
O~/d;'l-;:;
H+
M9~
H (in H2O)
'Nil.
SECTION 20.2 OXIDATION NUMBERS
[0.
-
F~
--....,~~~""'~
o.
S,
CQ.
r\S
-~
H
( ih
~
-=---...~-- ......" ....- - - . ­
I-t'"
t
~-
"""'_'~'lW:OO
l.{
0)
N~
1
1. Give the oxidation number of each kind of atom or ion. a. Sn
Jlf
c. Sz­
-2.
e. Se
b. Ki-
+1
d. Fe3 +
+3
f. Mg2+ "'2
fi1
2. Calculate the oxidation number of chromium in each of the following fonnulas. a. CrZ03
b. H zCrz0 7
c. CrS04
d. Cr0 42
-
(31.
',-",
®
@
Use the changes in oxidation number to determine which elements are oxidized
and which are reduced in these reactions. (Note: It is not necessary to use balanced reactions.) o'lCidi2.ed redl)ttd
+ H 2S04 - CO 2 + SOz + H 20 b. HN0 3 + HI - NO + I2 + HzO
c. KMn0 4 + HCl- MnClz + Clz + H 20 + KCl
a. C
. ......;
'
...
@
@
d. Sb
Q
.
C
b . I (In HI~
5 (,n
i-' • •
~l.S()q)
, .
' . "~ ..
N (i~ HN 0 3 ;: '
c. C\ (i", "(~ Mn (in l<r100
N. (in HNO
d . C;b
+ HN03 - SbzOs + NO + H 20
@F or each reaction in problem 3 above, identify the oxidizing agent and reduclllg agent. ~
wh~te"H \rJ~5 c)(idi"2td
I
i5
C.Q
\led the
f'e.OllC.IV\':) Q~e(\+. Chapter 20 Oxidation-Reduction Reactions
523
: