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Essential Chemistry for IGCSE - Chemical Changes (Section 4)

1
If a reaction has a negative enthalpy change (ΔH), is the reaction exothermic or endothermic?
Answer
(A)
Exothermic
2
Which change is an example of a chemical change?
Answer
(C)
Baking a cake
3
How is the heat generated by the nuclear fission used in a power plant?
Answer
(B)
To drive turbines by heating water to produce steam.
4
What is a key benefit of hydrogen fuel cells?
Answer
(A)
Low emissions
5
What component of a nuclear power plant converts nuclear energy into electrical energy?
Answer
(B)
Turbine
6
What is the enthalpy change, ΔH, for an endothermic reaction?
Answer
(A)
Positive
7
What process generates heat in a nuclear power plant?
Answer
(A)
Nuclear fission
8
Which statement best describes bond breaking?
Answer
(B)
It absorbs energy.
9
What does nuclear fission in a power plant ultimately create?
Answer
(A)
Heat.
10
What is one of the major drawbacks of relying on fossil fuels?
Answer
(B)
They contribute to air pollution.
11
What do we call fuels made from ancient plant or animal matter?
Answer
(B)
Fossil fuels
12
Which is a non-renewable energy resource?
Answer
(C)
Coal
13
What is the difference between a physical and chemical change?
Answer
(C)
Physical changes alter the state or form but not the composition.
14
What type of reaction occurs at the anode of an electrochemical cell?
Answer
(A)
Oxidation
15
Which of the following is a characteristic of a fuel?
Answer
(A)
Releases energy when burned
16
In a nuclear power plant, what controls the rate of the nuclear reaction?
Answer
(C)
Control rods
17
What is the main source of fuel for fuel cells?
Answer
(A)
Hydrogen
18
What type of change is often associated with a positive enthalpy change (ΔH)?
Answer
(B)
Endothermic reactions
19
What is the overall function of an electrochemical cell?
Answer
(B)
To convert chemical energy into electrical energy.
20
What does the energy level diagram of an exothermic reaction show?
Answer
(B)
The reactants have more energy than the products.
21
In an electrochemical cell, which electrode is the site of oxidation?
Answer
(B)
The anode
22
Which of the following is an example of a chemical change?
Answer
(C)
Rusting of iron
23
What type of fuel is formed from the decay of plants which increased in the absence of oxygen?
Answer
(A)
Coal
24
In an exothermic reaction, the energy of the products compared to the reactants is:
Answer
(B)
Lower
25
How is electricity generated in a nuclear power plant?
Answer
(C)
By using heat from the reactor to boil water and turn a turbine.
26
What is the process called where the nucleus of an atom splits?
Answer
(B)
Fission
27
What is the primary fuel used in nuclear power plants?
Answer
(C)
Uranium
28
What is the term for a reaction that absorbs energy from its surroundings?
Answer
(B)
Endothermic
29
What is the role of a fuel in a power plant?
Answer
(B)
To heat water to produce steam.
30
Which of the following is not a result from burning fossil fuels?
Answer
(D)
Increased oxygen levels
31
Which of the following is an example of a fossil fuel?
Answer
(C)
Coal
32
What process releases heat to generate electricity in nuclear power plants?
Answer
(B)
Nuclear fission
33
Which of the following statements best describes the function of a fuel cell?
Answer
(B)
It converts chemical energy directly into electrical energy.
34
Which of the following statements is true regarding bond breaking and bond making?
Answer
(B)
Bond breaking requires energy; bond making releases energy.
35
What is the primary environmental concern associated with the use of fossil fuels?
Answer
(C)
Global warming
36
Which electrode in an electrochemical cell is the negative electrode?
Answer
(A)
Anode
37
What are the two main products of an ideal hydrogen fuel cell?
Answer
(D)
Electricity and water
38
If a reaction absorbs heat from the surroundings, it is classified as:
Answer
(B)
Endothermic
39
Which of the following components are present in a fuel cell?
Answer
A
B
C
40
During which process is energy usually released?
Answer
(B)
Bond forming
41
Which of the following indicates a chemical change?
Answer
(C)
Iron rusting
42
What is the primary function of a fuel cell?
Answer
A
C
43
Which of the following is a key advantage of fuel cells over traditional combustion engines?
Answer
(C)
They do not emit greenhouse gases.
44
Which of the following describes what happens during bond making?
Answer
(B)
Energy is released.
45
Which is the primary product of a hydrogen fuel cell?
Answer
(C)
Water
46
What energy transformation is happening in an electrochemical cell?
Answer
(A)
Chemical to electrical
47
What is the function of the electrolyte in an electrochemical cell?
Answer
(B)
To allow ion movement
48
Which component allows the movement of ions to complete a circuit in a simple electrochemical cell?
Answer
(C)
Electrolyte
49
What is the core component of a nuclear reactor that undergoes fission?
Answer
(B)
Uranium fuel rods
50
In an energy level diagram, which of the following would indicate an exothermic reaction?
Answer
(B)
The products are at a lower energy level than the reactants.