CHEMISTRY 1.0 Flashcards
(113 cards)
1
Q
What is the anode material in a dry cell battery?
A. Carbon
B. Zinc
C. Lithium
D. Mercury
A
B
2
Q
Which component in a dry cell acts as the electrolyte?
A. Sulfuric acid
B. Gelled ammonium chloride and zinc chloride
C. Manganese dioxide
D. Lead oxide
A
B
3
Q
Which battery is commonly used in automobiles?
A. Lithium-ion
B. Dry cell
C. Lead-acid
D. Nickel-cadmium
A
C
4
Q
Which material is the cathode in a lithium-ion battery?
A. Graphite
B. Lithium cobalt oxide
C. Zinc
D. Carbon
A
B
5
Q
What is the byproduct of a hydrogen-oxygen fuel cell?
A. Water
B. Carbon dioxide
C. Hydrogen peroxide
D. Methane
A
A
6
Q
Which battery type is declining in use due to environmental toxicity?
A. Mercury battery
B. Lithium-ion battery
C. Dry cell battery
D. Fuel cell
A
A
7
Q
What characteristic makes lithium-ion batteries suitable for portable electronics?
A. High energy density
B. Long recharge time
C. Low weight-to-capacity ratio
D. Low cost
A
A
8
Q
Which reaction occurs in the anode of a fuel cell?
A. Oxidation of hydrogen
B. Reduction of oxygen
C. Oxidation of zinc
D. Reduction of water
A
A
9
Q
Which material is oxidized in a lead storage battery?
A. Lead
B. Zinc
C. Mercury
D. Graphite
A
A
10
Q
What is the electrolyte used in a lead-acid battery?
A. Potassium hydroxide
B. Sulfuric acid
C. Zinc chloride
D. Sodium hydroxide
A
B
11
Q
What happens when the anode material in a dry cell is depleted?
A. The battery continues to operate.
B. The battery stops producing electricity.
C. The cathode becomes the anode.
D. The electrolyte reacts more rapidly.
A
B
12
Q
What is the primary use of a fuel cell?
A. To store energy
B. To convert chemical energy into electricity
C. To generate heat
D. To regulate current in a circuit
A
B
13
Q
How does a lithium-ion battery achieve high cycle life?
A. Through a gelled electrolyte
B. By using reversible reactions
C. By preventing oxidation
D. Through a high voltage output
A
B
14
Q
What is the function of the separator in a lithium-ion battery?
A. To conduct electrons
B. To allow ions to flow between electrodes
C. To prevent short circuits
D. To store energy
A
B
14
Q
What type of battery is most commonly used in mobile phones?
A. Lead-acid
B. Lithium-ion
C. Mercury
D. Alkaline
A
B
15
Q
Which of the following is a limitation of mercury batteries?
A. High cost
B. Limited shelf life
C. Toxicity of mercury
D. Low voltage
A
C
16
Q
In a lead-acid battery, what forms at the anode during discharge?
A. Lead oxide
B. Lead sulfate
C. Zinc oxide
D. Magnesium sulfate
A
B
17
Q
What is the main function of the cathode in a dry cell battery?
A. To release electrons
B. To conduct ions
C. To accept electrons
D. To store energy
A
C
18
Q
What is the primary cause of battery failure in lithium-ion cells?
A. Voltage surge
B. Overheating or overcharging
C. Internal short circuit
D. Corrosion of terminalsB
A
B
19
Q
What type of reaction occurs at the cathode in a fuel cell?
A. Oxidation of hydrogen
B. Reduction of oxygen
C. Oxidation of zinc
D. Reduction of carbon dioxide
A
B
20
Q
What type of corrosion occurs due to dissimilar metals in contact?
A. Uniform corrosion
B. Galvanic corrosion
C. Pitting corrosion
D. Exfoliation corrosion
A
B
21
Q
Which ion is commonly associated with triggering pitting corrosion?
A. Sulfate
B. Chloride
C. Phosphate
D. Nitrate
A
B
22
Q
Which type of corrosion involves tensile stress?
A. Uniform corrosion
B. Pitting corrosion
C. Stress corrosion cracking
D. Galvanic corrosion
A
C
23
Q
What happens to the anodic material in galvanic corrosion?
A. It corrodes.
B. It remains intact.
C. It forms a protective oxide layer.
D. It bonds with the cathodic material.
A
A
24
Which type of corrosion is most dangerous due to localized material loss?
A. Uniform corrosion
B. Exfoliation corrosion
C. Galvanic corrosion
D. Pitting corrosion
D
25
What type of corrosion commonly occurs in marine environments?
A. Pitting corrosion
B. Exfoliation corrosion
C. Stress corrosion cracking
D. Uniform corrosion
A
26
Why does stainless steel resist corrosion?
A. It contains a protective layer of zinc.
B. It has a chromium oxide protective layer.
C. It does not react with oxygen.
D. It is an alloy of aluminum and magnesium.
B
27
What is the main factor that accelerates corrosion in a humid environment?
A. Temperature
B. Presence of oxygen
C. Moisture
D. Acidity
C
28
What is the primary cause of galvanic corrosion?
A. Excessive pressure on the metal
B. Contact between dissimilar metals in the presence of an electrolyte
C. High temperature exposure
D. Oxygen exposure
B
29
Which type of corrosion can lead to catastrophic failure due to small localized pits?
A. Stress corrosion cracking
B. Galvanic corrosion
C. Pitting corrosion
D. Exfoliation corrosion
C
30
What metal is commonly used in sacrificial anodes for cathodic protection?
A. Aluminum
B. Zinc
C. Copper
D. Iron
B
30
What is the effect of moisture on corrosion rates?
A. It accelerates corrosion
B. It decreases corrosion
C. It has no effect
D. It protects the metal
A
31
Which type of corrosion involves the separation of layers of material?
A. Pitting corrosion
B. Exfoliation corrosion
C. Stress corrosion cracking
D. Uniform corrosion
B
32
How can galvanic corrosion be prevented?
A. By using the same metal for both components
B. By using plastic components
C. By increasing the exposure to moisture
D. By reducing the temperature
A
33
What is the result of stress corrosion cracking?
A. Material weakens and cracks under stress
B. A protective layer forms on the metal
C. The metal becomes resistant to further corrosion
D. The metal becomes stronger
A
34
What type of corrosion is most commonly observed in pipelines?
A. Uniform corrosion
B. Stress corrosion cracking
C. Pitting corrosion
D. Galvanic corrosion
A
35
Which of the following metals is highly resistant to corrosion in seawater?
A. Aluminum
B. Iron
C. Stainless steel
D. Copper
A
36
What is the effect of chloride ions on corrosion?
A. It accelerates corrosion
B. It has no effect
C. It prevents corrosion
D. It causes the formation of protective layers
A
37
Which method involves coating steel with zinc?
A. Electroplating
B. Anodizing
C. Galvanizing
D. Passivation
C
38
What does painting do to prevent corrosion?
A. Prevents electron transfer
B. Forms a chemical bond with oxygen
C. Acts as a physical barrier
D. Reduces moisture absorption
C
39
Which process thickens the natural oxide layer on aluminum?
A. Electroplating
B. Cathodic protection
C. Alloying
D. Anodizing
D
40
Which material is often used as a sacrificial anode?
A. Aluminum
B. Magnesium
C. Iron
D. Copper
B
41
What is the purpose of passivation?
A. To increase metal conductivity
B. To form a stable protective oxide layer
C. To coat the metal with zinc
D. To create an alloy
B
42
How does electroplating prevent corrosion?
A. By forming a protective oxide layer
B. By applying a sacrificial layer
C. By coating the surface with a more corrosion-resistant metal
D. By creating a barrier to oxygen
C
43
Which of the following materials is most commonly used for sacrificial anodes?
A. Magnesium
B. Copper
C. Zinc
D. Aluminum
A
44
What is the main function of a coating in corrosion prevention?
A. To prevent exposure to oxygen
B. To provide insulation
C. To increase electrical conductivity
D. To enhance surface hardness
A
45
What does anodizing do to metals like aluminum?
A. Creates a thicker, more durable oxide layer
B. Changes the color of the metal
C. Increases the conductivity of the metal
D. Prevents the formation of any oxide layer
A
45
What is the primary purpose of using a corrosion inhibitor?
A. To neutralize acidic environments
B. To enhance the strength of metals
C. To slow down the corrosion process
D. To increase temperature resistance
C
46
Which corrosion prevention method is commonly used in underground pipelines?
A. Painting
B. Anodizing
C. Cathodic protection
D. Galvanizing
C
47
Which material is used in a process known as passivation?
A. Iron
B. Stainless steel
C. Zinc
D. Aluminum
B
48
What is the purpose of using composite materials in corrosion prevention?
A. To improve aesthetic properties
B. To reduce weight and prevent corrosion
C. To increase strength
D. To lower the cost of manufacturing
B
49
Which of the following metals is commonly used for galvanizing steel?
A. Zinc
B. Copper
C. Iron
D. Nickel
A
50
What role do paints and coatings play in corrosion prevention?
A. They increase the conductivity of metals
B. They protect the metal by isolating it from environmental factors
C. They increase the temperature resistance of the metal
D. They make metals more conductive
B
51
What is a radioisotope?
A. A stable isotope
B. An isotope that emits radiation
C. An element with no neutrons
D. An isotope with high binding energy
B
52
Which particle is emitted during beta decay?
A. Proton
B. Neutron
C. Electron
D. Alpha particle
C
53
What is the binding energy of a nucleus?
A. Energy required to form a molecule
B. Energy needed to break apart a nucleus
C. Energy emitted during alpha decay
D. Energy absorbed during nuclear reactions
B
54
Which of the following isotopes undergoes alpha decay?
A. Carbon-14
B. Uranium-238
C. Tritium (Hydrogen-3)
D. Technetium-99m
B
55
What is the result of gamma decay?
A. A new element is formed
B. The nucleus loses energy without a change in atomic number
C. The atomic number decreases
D. The mass number increases
B
56
Which of the following is the primary purpose of using radiotracers?
A. To increase the binding energy of nuclei
B. To track chemical reactions without altering the system
C. To neutralize radioactive materials
D. To enhance the rate of radioactive decay
B
57
How is energy released in nuclear fission?
A. By combining light nuclei to form a heavier nucleus
B. By splitting a heavy nucleus into lighter nuclei
C. By emitting a proton from the nucleus
D. By capturing neutrons
B
58
Which of the following is true about nuclear fusion?
A. It requires low temperatures and low pressure
B. It occurs when two light nuclei combine to form a heavier nucleus
C. It produces radioactive waste
D. It is a process used in nuclear reactors
B
59
What type of radiation is emitted during beta-plus decay?
A. Electron
B. Positron
C. Neutron
D. Proton
A
59
Which isotope of hydrogen is used in fusion reactions?
A. Hydrogen-1
B. Hydrogen-2 (Deuterium)
C. Hydrogen-3 (Tritium)
D. Hydrogen-4
B OR C
60
What is the major advantage of nuclear fusion over fission?
A. Fusion produces no radioactive waste
B. Fusion reactions are easier to control
C. Fusion requires less energy input than fission
D. Fusion produces more energy per reaction than fission
D
61
Which element is commonly used as fuel in nuclear fission reactors?
A. Uranium-238
B. Uranium-235
C. Thorium-232
D. Plutonium-239
B
61
What is the result of a chain reaction in nuclear fission?
A. A nuclear explosion
B. A controlled release of energy
C. The emission of gamma radiation
D. The formation of new elements
A
62
A sample of carbon-14 weighs 200g initially. How much remains after 11,460 years (two half-lives)?
A. 50g
B. 100g
C. 25g
D. 200g
A
63
A radioactive substance decreases from 80g to 10g in 60 minutes. What is the half-life?
A. 10 minutes
B. 15 minutes
C. 20 minutes
D. 30 minutes
C
63
Calculate the decay constant (k) of an isotope with a half-life of 5730 years.
A. 0.000121 yr⁻¹
B. 0.00121 yr⁻¹
C. 0.0121 yr⁻¹
D. 0.121 yr⁻¹
A
64
What is the energy released during the formation of one mole of helium-4 nuclei from its nucleons?
A. 4 kJ
B. 400 kJ
C. 4,000 kJ
D. 40,000 kJ
C
65
Which process is represented by the equation U-235 + n → Kr-92 + Ba-141 + 3n\text{U-235 + n → Kr-92 + Ba-141 + 3n}?
A. Nuclear fusion
B. Nuclear fission
C. Radioactive decay
D. Alpha emission
B
66
Which of the following isotopes is commonly used for medical imaging?
A. Carbon-14
B. Technetium-99m
C. Uranium-235
D. Polonium-210
B
67
What is the significance of the mass defect in nuclear reactions?
A. It represents energy loss as heat.
B. It represents the difference between the mass of nucleons and the nucleus.
C. It determines the rate of nuclear decay.
D. It is the main cause of radioactive emissions.
B
68
What type of radiation is emitted when a neutron is converted to a proton?
A. Alpha radiation
B. Beta-minus radiation
C. Beta-plus radiation
D. Gamma radiation
B
68
. A radioactive isotope has a half-life of 3 days. If 64g of the substance is present initially, how much remains after 9 days?
A. 64g
B. 32g
C. 8g
D. 4g
C
69
Calculate the energy released if the mass defect of a nuclear reaction is 0.03 atomic mass units (1 amu = 931.5 MeV/c2931.5 \, \text{MeV/c}^2).
A. 27.9 MeV
B. 31.1 MeV
C. 0.279 MeV
D. 0.931 MeV
A
70
49. How is the energy released in nuclear reactions related to the mass defect?
A. Energy is released because mass is converted into energy
B. Energy is absorbed to create mass from energy
C. Mass increases in nuclear reactions
D. Energy is released in the form of light
A
71
Which of the following best describes the mass-energy equivalence principle?
A. Mass is always conserved in chemical reactions
B. Mass and energy are interchangeable according to E=mc2E = mc^2E=mc2
C. Mass is converted into heat in chemical reactions
D. Energy is required to convert mass into chemical bonds
B
72
What is radioactive decay?
A. The process of forming stable isotopes
B. The spontaneous breakdown of an unstable nucleus
C. The emission of protons from a stable nucleus
D. The increase in energy of a stable isotope
B
73
Which type of decay involves the emission of a helium nucleus?
A. Beta decay
B. Alpha decay
C. Gamma decay
D. Positron emission
B
73
What happens to the atomic number during beta-minus decay?
A. It increases by 1
B. It decreases by 1
C. It remains the same
D. It doubles
A
74
Which of the following best defines half-life?
A. The time it takes for half of a radioactive sample to decay
B. The time required for a nucleus to emit one alpha particle
C. The time it takes for all radioactive material to stabilize
D. The time taken for radiation to reach half its energy level
A
75
Which of the following isotopes is used in carbon dating?
A. Uranium-235
B. Carbon-12
C. Carbon-14
D. Technetium-99
C
75
If the half-life of a substance is 10 years, how much remains after 30 years from an initial 80g sample?
A. 10g
B. 20g
C. 40g
D. 5g
A
76
If a fossil has 25% of its original carbon-14 remaining, how many half-lives have passed?
A. 1
B. 2
C. 3
D. 4
B
77
What is nuclear fusion?
A. The process of splitting a nucleus into smaller parts
B. The combination of two light nuclei to form a heavier nucleus
C. The emission of radiation from an unstable nucleus
D. The chain reaction of uranium nuclei
B
78
What is the primary fuel for nuclear fusion in stars?
A. Helium
B. Hydrogen
C. Carbon
D. Uranium
B
79
What is critical mass in nuclear fission?
A. The smallest amount of fuel required to sustain a chain reaction
B. The maximum energy released during fission
C. The minimum energy required to split a nucleus
D. The amount of energy needed to fuse nuclei
A
80
Which of the following represents a fission reaction?
A. H-2 + H-3 → He-4 + n\text{H-2 + H-3 → He-4 + n}
B. U-235 + n → Kr-92 + Ba-141 + 3n\text{U-235 + n → Kr-92 + Ba-141 + 3n}
C. C-14 → N-14 + e⁻\text{C-14 → N-14 + e⁻}
D. He-4 → He-3 + p\text{He-4 → He-3 + p}
B
81
Which condition is required for nuclear fusion to occur?
A. Low pressure and high temperature
B. High temperature and high pressure
C. High temperature and low pressure
D. Low temperature and low pressure
B
81
What is binding energy?
A. The energy required to break apart a nucleus
B. The energy released during alpha decay
C. The energy that holds protons and neutrons together in a nucleus
D. The energy used to form chemical bonds
A
82
Which equation relates mass defect to energy?
A. E=mc2E = mc^2
B. E=12mv2E = \frac{1}{2}mv^2
C. E=hνE = h\nu
D. E=kq2/r2E = kq^2/r^2
A
83
Why is Iron-56 considered the most stable nucleus?
A. It has the highest binding energy per nucleon.
B. It undergoes radioactive decay the fastest.
C. It can easily split into lighter nuclei.
D. It forms a stable isotope after beta decay.
A
84
How does mass defect result in energy release?
A. Mass is converted into energy according to E=mc2E = mc^2.
B. Energy is absorbed to reduce the mass of the nucleus.
C. Mass increases during nuclear reactions.
D. Mass defect is unrelated to energy release.
A
85
1. A battery is an arrangement of electrolytic cells.
a) True
b) False
Answer: b
Explanation: A battery is not an arrangement of electrolytic cells, but an arrangement of electrochemical cells. An electrochemical cell is one which converts chemical energy into electrical energy whereas an electrolytic cell is one which converts electrical energy into chemical energy. Since batteries convert chemical energy to electrical energy, it is an arrangement of electrochemical cells.
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2. Which of the following is not a requirement for a useful battery?
a) It should be light and compact
b) It should have a reasonable life span
c) It should ideally have a constant voltage throughout its lifespan
d) It should supply Alternating Current(AC)
Answer: d
Explanation: A useful battery is expected to be light and compact to be easily transported. It is expected to have a reasonable lifespan to justify its usage. Its voltage should not vary appreciably during usage so that it doesn’t adversely affect the circuit it is used in. A battery supplies Direct Current(DC) and not Alternating Current(AC).
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3. Which of the following statements is true regarding a primary cell?
a) The electrode reactions can be reversed
b) It can be recharged
c) An example of a primary cell is a mercury cell
d) An example of a primary cell is a nickel-cadmium storage cell
C
88
4. Secondary cells are also called storage cells.
a) True
b) False
Answer: a
Explanation: Secondary cells are those cells in which the electrode reaction can be reversed by applying an electrical energy. Therefore, they can be used to store electrical energy. So, they are also known as storage cells.
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5. Which of the following is used as an anode in a dry cell?
a) Zinc
b) Graphite
c) Mercury(II) oxide
d) Nickel
Answer: c
Explanation: A dry cell is constructed using zinc and graphite. It consists of a zinc cylinder through whose centre passes a graphite rod. The zinc cylinder acts as an anode, whereas the graphite rod acts as a cathode.
90
6. Why do leak proof dry cells have an iron or steel sheet covering the zinc cylinder?
a) It increases the potential difference between the anode and cathode
b) It acts as a barrier around the zinc cylinder which can develop holes during use
c) It makes it waterproof
d) It prevents the leakage of current
Answer: b
Explanation: In a dry cell, zinc loses electrons and the zinc ions dissolve into the electrolyte. As a result, the zinc cylinder of the dry cell develops holes as it is used. To prevent the leakage of electrolyte through these holes, an iron or steel sheet is used to cover the cylinder.
91
8. What is the role of manganese dioxide in a dry cell?
a) It acts as an electrolyte
b) It acts as the cathode
c) It acts as an anode
d) It acts as a depolariser
Answer: d
Explanation: In a dry cell, in the remaining space between the electrolyte and the graphite cathode, a second paste consisting of ammonium chloride and manganese dioxide is applied. The manganese dioxide acts as a depolariser as it helps to prevent the build-up of hydrogen gas bubbles.
92
7. Which of the following is the electrolyte used in a dry cell?
a) Ammonium chloride
b) Manganese dioxide
c) Potassium hydroxide
d) Sulphuric acid
Answer: a
Explanation: The electrolyte in a dry cell is ammonium chloride in the form of a moist paste placed next to the zinc anode. In some dry cells marketed as “heavy-duty”, the ammonium chloride is replaced by zinc chloride.
93
9. What is the final oxidation state of manganese after the electrochemical reactions in a dry cell?
a) +4
b) +3
c) +2
d) +1
Answer: b
Explanation: In a dry cell, in the cathode reaction, manganese dioxide(MnO2) is reduced to form manganese oxide-hydroxide(MnO(OH)). In this process, the oxidation state of manganese changes from +4 to +3. Hence the final oxidation state of manganese is +3.
94
10. Which of the following scientists invented the first dry cell?
a) Carl Gassner
b) Nikola Tesla
c) Antione Lavoisier
d) Georges Leclanché
Answer: a
Explanation: In the year 1886, Carl Gassner obtained a German patent on a variant of the wet Leclanché cell, which can be known as the dry cell because it did not have a liquid electrolyte. Instead, a mixture of ammonium chloride and plaster of paris was used.
95
11. What is the final product that zinc forms during the functioning of a mercury cell?
a) ZnO
b) ZnO2
c) Zn
d) Zn(OH)2
Answer: a
Explanation: A mercury cell consists of a zinc anode and a mercury(II) oxide cathode. Potassium hydroxide is used as the electrolyte. In the electrochemical reaction, zinc is oxidised to become zinc oxide(ZnO) whereas mercury(II) oxide is reduced to elemental mercury.
96
12. Which of the following appliances would not use sodium hydroxide as an electrolyte in their mercury cells?
a) Calculators
b) Hearing aids
c) Electronic watches
d) Photographic cameras with a flash
Answer: d
Explanation: Sodium hydroxide cells have nearly constant voltage at low discharge currents whereas potassium hydroxide cells provide a constant voltage at high discharge currents. Therefore, sodium hydroxide cells are ideal for calculators, hearing aids and electronic watches whereas potassium hydroxide cells are ideal for photographic cameras with a flash.
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13. Which of the following is the voltage output of a mercury cell?
a) 1.55V
b) 1.35V
c) 2.55V
d) 1V
Answer: b
Explanation: Mercury batteries use a reaction between mercuric oxide and zinc in an alkaline electrolyte to produce electricity. Its voltage during discharge is a constant 1.35V. The common dry cell, on the other hand, provides a voltage of 1.5V.
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14. Which of the following statements is not true with respect to a lead storage cell (or a lead-acid battery)?
a) The electrolyte used is an aqueous solution of sulphuric acid
b) The anode is made up of lead
c) The cathode is made up of lead(IV) oxide
d) It is a primary cell
Answer: d
Explanation: A lead storage cell is a secondary cell which has a grid of lead packed with finely divided spongy lead for an anode and a grid of lead packed with lead(IV) oxide for a cathode. The electrolytic solution used in a lead-acid battery is an aqueous solution of sulphuric acid.
99
15. Which of the following products are formed when a lead storage battery is discharged?
a) SO2
b) Pb
c) PbO2
d) PbSO4
Answer: d
Explanation: During the working of the lead storage battery, PbSO4 is formed at both the electrodes and sulphuric acid is used up. At the anode, Pb is oxidised to form PbSO4 and at the cathode, PbO2 is reduced to form PbSO4.
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