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Essential Chemistry for IGCSE - Electricity And Chemistry (Section 7)

1
Which of the following is the chemical formula for cryolite?
Answer
(B)
Na3AlF6
2
Which of the following correctly states where the reduction reaction takes place in an electrolytic cell? (Select all that apply)
Answer
(B)
Cathode
3
Which substances are good conductors of electricity?
Answer
A
B
D
4
Which of the following statements is TRUE regarding the melting point of aluminium oxide in cryolite?
Answer
(B)
The melting point decreases.
5
Which of the following is NOT a purpose of insulators?
Answer
(C)
Allowing electrons to flow freely.
6
Which of the following reactions occurs at the anode during the electrolysis of copper sulfate solution using copper electrodes?
Answer
(B)
Cu -> Cu2+ + 2e-
7
What is the main purpose of using a diaphragm in the electrolysis of brine?
Answer
(B)
To separate the products.
8
Which of the following is a key application of electrolysis in industrial settings?
Answer
(A)
Extraction of precious metals
9
What are the main impurities found in bauxite ore?
Answer
(B)
Iron oxides, silicon oxides, and titanium oxides.
10
What is the role of the steel core in steel-cored aluminum cables?
Answer
(B)
To increase strength and prevent sagging.
11
Which of the following materials are commonly used for the insulation of electrical wiring?
Answer
A
B
D
12
What is the first step in the extraction of aluminum from bauxite ore?
Answer
(C)
Purifying the ore using sodium hydroxide.
13
What is formed at the cathode during the electrolysis of acidified water?
Answer
(B)
Hydrogen gas
14
What is the process by which copper ions are converted into copper atoms during the electrolysis of copper sulfate solution?
Answer
(B)
Reduction
15
What process is used to coat an object with a thin layer of another metal?
Answer
(B)
Electroplating
16
Why are very thick wires used in high-voltage power lines?
Answer
(D)
All of the above.
17
What is the purpose of the electrolyte in an electroplating setup?
Answer
(B)
To carry the current in the solution.
18
What type of current is often used in high-voltage power lines?
Answer
(A)
Alternating current
19
What materials are the best conductors of electricity?
Answer
A
B
C
20
What is the process called where an ionic compound is broken down when electricity is passed through it?
Answer
(C)
Electrolysis
21
What is the purpose of the electrolyte in an electrolytic cell?
Answer
(B)
To complete the circuit by allowing the flow of ions.
22
What will be the products when a solution of copper (II) chloride is electrolysed, using inert electrodes?
Answer
(B)
Copper and chlorine
23
Which of the following is used in the electroplating process?
Answer
(B)
Direct current (DC)
24
Which of the following statements is/are true regarding the electrolysis of molten aluminum oxide?
Answer
B
C
25
In the purification of copper by electrolysis, what material is used as the cathode?
Answer
(A)
Pure copper
26
Why is aluminium used in high-voltage power lines
Answer
A
C
D
27
What can cause the electrical current to heat up during the passage of current through wires?
Answer
(A)
High resistance
28
During the electrolysis of molten lead(II) bromide, which of the following statements is correct?
Answer
(C)
Lead ions are reduced at the cathode.
29
In the purification of copper, which electrode is made of impure copper?
Answer
(B)
Anode
30
What is the electrical conductivity of a material which acts as an insulator?
Answer
(C)
Low.
31
In the industrial extraction of aluminium, what materials do you need?
Answer
A
B
C
32
Which of the following is NOT a product formed during the electrolysis of molten NaCl?
Answer
(C)
Hydrogen
33
Which of the following processes is used in the large-scale extraction of copper from its ores?
Answer
(D)
Electrolysis and purification.
34
Why is aluminum used in high-voltage power lines?
Answer
A
C
D
35
In the electrolytic refining of copper, what happens to the copper ions (Cu²⁺) in the electrolyte?
Answer
(C)
They are reduced at the cathode.
36
Which of the following best describes the process of electroplating?
Answer
(B)
Depositing a thin layer of metal onto an object using electricity.
37
During the electrolysis of molten aluminum oxide, where does the oxygen come from?
Answer
(D)
From the cathode.
38
Which of the following statements is true about the anode in an electrolytic cell? (Select all that apply)
Answer
A
B
D
39
Which of the following compounds is used as an electrolyte in the extraction of aluminum?
Answer
(B)
Cryolite.
40
Which of the following is an example of an insulator?
Answer
(C)
Wood
41
When electroplating an object, which electrode is the object itself?
Answer
(B)
Cathode
42
In the electrolysis of molten lead(II) bromide (PbBr2), what is produced at the anode?
Answer
(B)
Bromine
43
When a more reactive metal is electroplated, the less reactive metal will be the...
Answer
(A)
Cathode
44
What is the formula of aluminum oxide?
Answer
(B)
Al2O3
45
What happens to the mass of the anode during the refining of copper?
Answer
(A)
It decreases
46
What is the most common use of copper in electrical wiring?
Answer
(A)
Because it is a good conductor of electricity
47
What would happen if aluminum was used instead of steel for the core of the high-voltage cable?
Answer
(C)
The cable would sag more.
48
Which of the following statements is true regarding the reaction that occurs at the cathode during the electrolysis of aluminum oxide?
Answer
(B)
Aluminum ions are reduced.
49
During electrolysis of aluminum oxide, what would be the final product at the cathode?
Answer
(A)
Aluminium metal
50
In the extraction of aluminum, what is the main reason why it is important to replace the carbon anodes periodically?
Answer
(C)
Because they are 'burned away' by reacting with the oxygen produced.