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WorksheetsRevisão REDOX
Total questions: 18
Worksheet time: 13mins
Name
Class
Date
1.
What is oxidation number of O in O2 ?
a)
0
b)
-2
c)
+1
d)
+2
2.
What is the oxidation number of chlorine in HClO?
a)
0
b)
-1
c)
+1
d)
+5
3.
Oxidation is the _________ of electrons.
a)
loss
b)
gain
c)
sharing
d)
transfer
4.
Reduction is the ___________ of electrons.
a)
loss
b)
gain
c)
sharing
d)
transfer
5.
What is the oxidation number of nitrogen in N2?
a)
-3
b)
0
c)
+4
d)
-1
6.
The sum of the oxidation numbers in SCN- is equivalent to
a)
0
b)
-1
c)
+1
d)
+3
7.
The sum of the oxidation numbers in Na2CO3 is equivalent to
a)
0
b)
-2
c)
+1
d)
-1
8.
What is the oxidation number of iodine in KIO3?
a)
0
b)
-1
c)
+5
d)
+1
9.
Determine the oxidation number of chromate in CrO42-.
a)
+6
b)
0
c)
+2
d)
+3
10.
Which of the following represents reduction?
a)
C → CO
b)
N2 → NH3
c)
Zn → Zn2+
d)
H2 → H2O
11.
In the reaction Zn + 2HCl --> ZnCl2 + H2
which element, if any, is oxidized?
a)
Zinc
b)
Hydrogen
c)
Chlorine
d)
None
12.
In the reaction
2Ca(s) + O2(g) --> 2CaO(s), calcium is __________
2Ca(s) + O2(g) --> 2CaO(s), calcium is __________
a)
Reduced
b)
Synthesized
c)
Oxidized
d)
None of the above
13.
Which statement is true:
Mg → Mg2+ + 2e–
Mg → Mg2+ + 2e–
a)
Mg gains 2 electrons
b)
Mg2+ loses 2 electrons
c)
Mg loses 1 electron
d)
Mg loses 2 electrons
14.
What substance is oxidized in the following reaction?
4Fe + 3O2 --> 2Fe2O3
4Fe + 3O2 --> 2Fe2O3
a)
Iron
b)
Fluorine
c)
Oxygen
15.
Is calcium oxidized or reduced in the following reaction?
2CaO--> 2Ca + O2
2CaO--> 2Ca + O2
a)
Oxidized
b)
Reduced
16.
Which of the following half reactions correctly represents a reduction half reaction?
a)
Fe →Fe2+ + 2e-
b)
Pb4+ + 2e- →Pb2+
c)
2O-2 →O2 + 4e-
d)
Fe + 3e- →Fe3+
17.
If in a reaction, copper is reduced; its number of electrons has:
a)
Increased
b)
Decreased
c)
Remained Constant
d)
Varies Randomly
18.
Which of the following represents oxidation?
a)
C → CH4
b)
Fe3+ → Fe2+
c)
Cl2 → 2Cl-
d)
Zn → ZnO
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