WorksheetsREDOX RKN
Total questions: 50
Worksheet time: 2hrs 8mins
Name
Class
Date
1.
Oxidation and reduction takes place
a)
simultaneously
b)
separately
2.
In a voltaic cell, the salt bridge is necessary for
a)
the movement of electrons to create a current
b)
the movement of ions to create a current
c)
the movement of electrons to maintain the neutrality of solution
d)
the movement of ions to maintain the neutrality of solution
3.
Is calcium oxidized or reduced in the following reaction?
2CaO--> 2Ca + O2
2CaO--> 2Ca + O2
a)
Oxidized
b)
Reduced
4.
In the reaction Zn + H2O --> ZnO2 + H2
which element, if any, is oxidized?
which element, if any, is oxidized?
a)
Zinc
b)
Hydrogen
c)
Oxygen
d)
None
5.
Which energy conversion shown below takes place in an electrochemical cell?
a)
Electrical to chemical
b)
Mechanical to chemical
c)
Mechanical to electrical
d)
Chemical to electrical
6.
What is oxidation number of Cr in Cr2O72-?
a)
-2
b)
+2
c)
+6
d)
+12
7.
What is oxidation number of Fe in FeO ?
a)
+2
b)
-2
c)
0
d)
+1
8.
What is the reducing agent of this reaction?
3Mg + N2−−−−> Mg3N2
3Mg + N2−−−−> Mg3N2
a)
Mg
b)
N2
c)
Mg3N2
d)
MgN
9.
Reduction happens at the
a)
anode
b)
cathode
c)
salt bridge
d)
voltmeter
10.
Select the correct half equation for Cu2+ ions forming Cu atoms.
a)
Cu2+ (aq) + 2e- —> Cu (s)
b)
Cu2+ (aq) - 2e- —> Cu (s)
c)
Cu2+ (aq) —> Cu (s) + 2e-
d)
Cu (aq) + 2e- —> Cu2+ (s)
11.
Select the correct half equation for dichromate ions forming chromium ions.
a)
Cr2O72-(aq) + 7H+(aq) + 6e- —> 2Cr3+(aq) + 7H2O(l)
b)
Cr2O72-(aq) + 14H+(aq) + 6e- —> Cr3+(aq) + 7H2O(l)
c)
Cr2O72-(aq) + 14H+(aq) + 6e- —> 2Cr3+(aq) + 14H2O(l)
d)
Cr2O72-(aq) + 14H+(aq) + 6e- —> 2Cr3+(aq) + 7H2O(l)
12.
Select the correct half equation for mangante ions forming manganese ions.
a)
MnO2(s) + 2H+(aq) + 2e- —> Mn2+(aq) + 2H2O(l)
b)
MnO2(s) + 4H+(aq) + 2e- —> Mn2+(aq) + 2H2O(l)
c)
MnO2(s) + 4H+(aq) + 2e- —> Mn2+(aq) + 4H2O(l)
d)
MnO2(s) + 4H+(aq) + e- —> Mn2+(aq) + 2H2O(l)
13.
If an atom loses electrons during a chemical reaction, the atom was:
a)
Oxidized
b)
Reduced
c)
Neutralized
d)
Precipitated
14.
A chemical reaction that involves a gain/loss of electrons is called:
a)
Double Replacement
b)
Neutralization
c)
Oxidation-Reduction
d)
Hydrolysis
15.
Which of the following will always have an oxidation number of +1 when in a compound?
a)
Mg
b)
Ca
c)
Na
d)
S
16.
As a free element (uncombined), oxygen will have an oxidation number of ?
a)
+1
b)
-1
c)
0
d)
+2
17.
What compound is the Oxidizing Agent?
a)
HNO3
b)
H2S
c)
NO
d)
H2O
18.
What compound is the Reducing Agent?
a)
HNO3
b)
H2S
c)
NO
d)
H2O
19.
Another name for a "oxidation-reduction" reaction is
a)
chemical reaction
b)
neutralization reaction
c)
redox reaction
d)
nuclear reaction
20.
What is the oxidation number of N in NO2-1?
a)
-3
b)
+4
c)
-2
d)
+3
21.
N2 +O2 --> 2NO
Determine which substance is oxidized and which is reduced.
Determine which substance is oxidized and which is reduced.
a)
Nitrogen is oxidized and Oxygen is reduced.
b)
Nitrogen is reduced and Oxygen is oxidized.
22.
What is oxidation number of H in H2O?
a)
0
b)
-2
c)
-1
d)
+1
23.
Which of the following is a physical changed?
a)
Sugar dissolved in a cup of coffee
b)
Over time an iron swing set becomes covered with rust
c)
Frost forms on the inside of a freezer
d)
Litmus paper turns pink when exposed to acid
24.
The purifying of an impure metal by oxidation followed by reduction is called
a)
electrowinning
b)
electrorefining
c)
electroforming
d)
anodizing
25.
The covering of a thin layer of metal is
a)
electrowinning
b)
electrorefining
c)
electroplating
d)
electromachining
26.
To electroplate an object it would have to be made to be the
a)
anode
b)
cathode
27.
The electrolysis of molten sodium chloride produces
a)
hydrochloric acid
b)
sodium metal and chlorine gas
c)
chlorine gas and aqueous sodium hydroxide
d)
glucose
28.
__________ is reduced in the following reaction:
Cr2O72- + 6 S2O32- + 14H+ > 2Cr3+ + 3S4O62- + 7H2O
Cr2O72- + 6 S2O32- + 14H+ > 2Cr3+ + 3S4O62- + 7H2O
a)
Cr2O72-
b)
S2O32-
c)
H+
d)
S4O62-
29.
What is the oxidation number of potassium in potassium permanganate?
a)
-1
b)
+3
c)
+1
d)
0
30.
The following is what type of reaction:
PbCl2 + AgNO3 → Pb(NO3)2 + AgCl
PbCl2 + AgNO3 → Pb(NO3)2 + AgCl
a)
Synthesis
b)
Decomposition
c)
Single Replacement
d)
Double Replacement
31.
What type of chemical reaction is this?
Al(OH)3 → Al2O3 + H2O
Al(OH)3 → Al2O3 + H2O
a)
Decomposition
b)
Combustion
c)
Synthesis
d)
Single Replacement
32.
The following is what type of reaction:
NH3 + HCl → NH4Cl
NH3 + HCl → NH4Cl
a)
Synthesis
b)
Decomposition
c)
Single Replacement Replacement
d)
Double Replacement Replacement
33.
Oxidation state of element is
a)
0
b)
+1
c)
-1
d)
no fixed oxidation state
34.
Oxidation state of group II element is always
a)
+1
b)
-1
c)
0
d)
+2
35.
.............. agent is a substance that causes another substance to be oxidized.
a)
Oxidizing
b)
Reducing
36.
.............. agent is a substance that causes another substance to be reduced.
a)
Oxidizing
b)
Reducing
37.
Thermal energy ALWAYS moves from _____ to _____.
a)
solid to liquid
b)
ice to water
c)
hot to cold
d)
solid to gas
38.
What is the oxidation number of Br in BrO3-1?
a)
+3
b)
-2
c)
+5
d)
+2
39.
What is oxidation number of P in K3PO4?
a)
+1
b)
+5
c)
-2
d)
0
40.
What is the oxidation state number of sulfur in SO32-?
a)
0
b)
+4
c)
+6
d)
+8
41.
What is the oxidation state number of chlorine in ClO3- ?
a)
0
b)
-5
c)
+5
d)
+7
42.
What is the oxidation state number of carbon in CF4?
a)
+2
b)
+4
c)
- 2
d)
- 4
43.
What is the oxidation state number of iron in Fe(NO3)2?
a)
0
b)
+2
c)
+3
d)
-2
44.
Which species is reduced in the following reaction?
H2 + F2 --> 2HF
H2 + F2 --> 2HF
a)
H2 is reduced to HF
b)
F2 is reduced to HF
45.
Wha is an Oxidation number?
a)
Number of atoms in a compound
b)
Number of elements in a compound
c)
Oxidation reaction
d)
the charge that atom would have if the compound was composed of ions
46.
Which of the following are numbers assigned to atoms and ions to keep track of electrons?
a)
charges
b)
ions
c)
coefficients
d)
oxidation numbers
47.
Which statement is true?
PbO + C → Pb + CO
PbO + C → Pb + CO
a)
PbO is oxidised by losing oxygen
b)
PbO is reduced by gaining oxygen
c)
C is reduced by gaining oxygen
d)
C is oxidised by gaining oxygen
48.
What is the oxidation numbers of sulfur in S8
a)
+8
b)
0
c)
-2
d)
+6
49.
What is the oxidation numbers of sulfur in sulfate ion
a)
-2
b)
0
c)
+6
d)
+2
50.
What is oxidation number of O in H2O2 ?
a)
-2
b)
-1/2
c)
+1
d)
-1
100 %
