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Unit 6: Energy sciences - Practice Quiz

CHE124 — Engineering Chemistry 60 Questions
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1 The calorific value of a fuel is defined as the amount of heat produced by the complete combustion of a:

Calorific value of fuels Easy
A. Unit mole of oxygen
B. Unit volume of air
C. Unit area of the fuel surface
D. Unit mass of the fuel

2 Which of the following is the standard SI unit for expressing the calorific value of a solid fuel?

Calorific value of fuels Easy
A.
B.
C.
D.

3 The difference between Gross Calorific Value (GCV) and Net Calorific Value (NCV) arises mainly due to the:

Calorific value of fuels Easy
A. Amount of ash formed
B. Presence of nitrogen gas
C. Latent heat of condensation of water vapour
D. Volume of the combustion chamber

4 Which instrument is commonly used in the laboratory to determine the calorific value of solid and liquid fuels?

determination of calorific value Easy
A. Bomb calorimeter
B. Ostwald viscometer
C. Bourdon gauge
D. Bunsen burner

5 Which calorimeter is typically used to determine the calorific value of gaseous fuels?

determination of calorific value Easy
A. Differential scanning calorimeter
B. Bomb calorimeter
C. Coffee cup calorimeter
D. Junkers calorimeter

6 The proximate analysis of coal determines moisture, volatile matter, ash and:

analysis of coal Easy
A. Sulphur content
B. Hydrogen content
C. Fixed carbon
D. Nitrogen content

7 Which type of coal analysis determines the percentage of elements such as carbon, hydrogen, nitrogen, sulphur and oxygen present in the coal sample by direct chemical estimation?

analysis of coal Easy
A. Thermal analysis
B. Ultimate analysis
C. Proximate analysis
D. Gravimetric titration

8 Which of the following is an example of a naturally occurring solid fuel?

energy sciences: fuels and its types Easy
A. Coal
B. Diesel
C. Petrol
D. Natural gas

9 Fuels are broadly classified based on their occurrence into primary fuels and:

energy sciences: fuels and its types Easy
A. Nuclear fuels
B. Renewable fuels
C. Liquid fuels
D. Secondary (derived) fuels

10 A key characteristic of a primary cell is that it:

Primary cells Easy
A. Can be recharged many times
B. Produces electricity from sunlight
C. Uses only liquid fuel as reactant
D. Cannot be recharged once discharged

11 Which of the following is a common example of a primary cell?

Primary cells Easy
A. Dry cell (Leclanché cell)
B. Lead-acid battery
C. Ni-Cd battery
D. Li-ion battery

12 Secondary batteries differ from primary cells because they are:

Secondary batteries Easy
A. Used only once and discarded
B. Powered by nuclear reactions
C. Unable to store any charge
D. Rechargeable and reusable

13 In a lead storage battery, the electrolyte used is:

Lead storage battery Easy
A. Sodium chloride solution
B. Dilute sulphuric acid
C. Potassium hydroxide
D. Hydrochloric acid

14 Lead storage batteries are most commonly used in:

Lead storage battery Easy
A. TV remote controls
B. Hearing aids
C. Automobiles
D. Wristwatches

15 In a lithium-ion battery, charge is carried between the electrodes by the movement of:

Li-ion battery Easy
A. Hydrogen ions
B. Chloride ions
C. Lithium ions ()
D. Electrons through the electrolyte

16 Which of the following devices most commonly uses a Li-ion battery?

Li-ion battery Easy
A. Wall clock powered by a single cell
B. Smartphone
C. Car ignition starter of a truck
D. Emergency torch with a zinc-carbon cell

17 The two active electrode materials used in a Ni-Cd battery are nickel oxide-hydroxide and:

Ni-Cd Easy
A. Lead
B. Cadmium
C. Zinc
D. Lithium

18 In a Ni-metal hydride (Ni-MH) battery, the negative electrode is made of:

Ni-metal hydride battery Easy
A. A hydrogen-absorbing metal alloy
B. Pure cadmium metal
C. Lead dioxide
D. Graphite rod

19 A fuel cell converts the chemical energy of a fuel directly into:

Fuel cells- principles, applications, advantages/disadvantages Easy
A. Nuclear energy
B. Sound energy
C. Mechanical energy
D. Electrical energy

20 Hydrogen is considered a clean energy carrier mainly because its combustion with oxygen produces:

hydrogen energy (production, storage, safety aspects) and significance as a clean and sustainable energy carrier Easy
A. Water
B. Carbon dioxide
C. Sulphur dioxide
D. Nitrogen oxides

21 In a Bomb calorimeter experiment, g of fuel raised the temperature of g of water by . Taking water equivalent of the apparatus as negligible and specific heat of water as , the gross calorific value of the fuel is approximately:

determination of calorific value Medium
A.
B.
C.
D.

22 Why is the Net (Lower) Calorific Value always less than the Gross (Higher) Calorific Value of a fuel?

determination of calorific value Medium
A. GCV ignores the sulphur content of the fuel
B. NCV is measured at higher pressure than GCV
C. Latent heat of condensation of water vapour is not recovered in NCV
D. NCV includes the heat of formation of ash

23 In the proximate analysis of coal, which property is determined by heating the coal sample in the absence of air at about after moisture removal?

analysis of coal Medium
A. Fixed carbon
B. Sulphur content
C. Volatile matter
D. Ash content

24 A coal sample has moisture, volatile matter, and ash by proximate analysis. What is the percentage of fixed carbon?

analysis of coal Medium
A.
B.
C.
D.

25 Which analysis of coal directly determines the percentage of C, H, N, S and O present in the coal?

analysis of coal Medium
A. Ultimate analysis
B. Bomb calorimetry
C. Thermogravimetric analysis
D. Proximate analysis

26 During the discharge of a Ni-Cd battery, what happens at the negative electrode?

Ni-Cd Medium
A. Cd is oxidized to
B. is oxidized to
C. is reduced to
D. Cd is reduced to metallic Cd

27 A major advantage of Ni-MH batteries over Ni-Cd batteries is that they:

Ni-metal hydride battery Medium
A. Deliver a much higher cell voltage per cell
B. Avoid toxic cadmium and offer higher energy density
C. Use a non-aqueous organic electrolyte
D. Are completely free from the memory effect

28 In a Li-ion battery, which process occurs at the graphite anode during charging?

Li-ion battery Medium
A. Intercalation of ions into graphite layers
B. De-intercalation of from graphite
C. Oxidation of lithium metal to
D. Reduction of cobalt oxide

29 Why can a non-aqueous (organic) electrolyte be preferred in Li-ion batteries instead of an aqueous one?

Li-ion battery Medium
A. Organic solvents conduct ions better than water
B. Aqueous electrolytes reduce the energy density unnecessarily
C. The high cell voltage would decompose water
D. Water increases the risk of memory effect

30 In a fully charged lead-acid battery, the material present at the cathode (positive plate) is:

Lead storage battery Medium
A.
B.
C.
D.

31 As a lead-acid battery discharges, the specific gravity of the electrolyte decreases because:

Lead storage battery Medium
A. Water evaporates from the electrolyte
B. dissolves and thickens the acid
C. is generated at both electrodes
D. is consumed and water is produced

32 What makes Li-air batteries theoretically attractive compared to conventional Li-ion batteries?

Li-air battery Medium
A. Very high theoretical energy density using oxygen from air as cathode reactant
B. They operate without any electrolyte
C. They completely eliminate the need for a lithium anode
D. They avoid the formation of any discharge products

33 Which of the following fuels generally has the highest gross calorific value per unit mass?

Calorific value of fuels Medium
A. Hydrogen
B. Coal
C. Natural gas (methane)
D. Petrol

34 Which characteristic best distinguishes a primary cell from a secondary cell?

Primary cells Medium
A. It can be recharged many times
B. Its cell reaction is irreversible and cannot be recharged
C. It uses a solid electrolyte only
D. It always delivers a higher voltage

35 Which of the following is NOT an example of a secondary (rechargeable) battery?

Secondary batteries Medium
A. Li-ion battery
B. Dry Leclanché cell
C. Ni-Cd battery
D. Lead-acid battery

36 In a - fuel cell, what reaction occurs at the anode?

Fuel cells- principles, applications, advantages/disadvantages Medium
A.
B.
C.
D.

37 A key advantage of fuel cells over conventional heat engines is that they:

Fuel cells- principles, applications, advantages/disadvantages Medium
A. Produce no reaction products at all
B. Operate only at very high temperatures for best efficiency
C. Store energy indefinitely without any fuel supply
D. Convert chemical energy directly to electricity, bypassing the Carnot limit

38 Which of the following is a set of only secondary (derived) fuels?

energy sciences: fuels and its types Medium
A. Uranium, coal, biomass
B. Wood, crude oil, natural gas
C. Coke, petrol, coal gas
D. Coal, petroleum, natural gas

39 Which method of hydrogen production is considered 'green hydrogen' with essentially zero carbon emissions?

hydrogen energy (production, storage, safety aspects) and significance as a clean and sustainable energy carrier Medium
A. Electrolysis of water using renewable electricity
B. Steam reforming of natural gas
C. Partial oxidation of hydrocarbons
D. Coal gasification

40 A major safety concern in the storage and handling of hydrogen gas is that it:

hydrogen energy (production, storage, safety aspects) and significance as a clean and sustainable energy carrier Medium
A. Reacts violently with inert gases like nitrogen
B. Is highly toxic and corrosive to the lungs
C. Is denser than air and accumulates near the ground
D. Has a very wide flammability range and low ignition energy

41 In a bomb calorimeter experiment, g of a fuel raises the temperature of g of water by . The water equivalent of the apparatus is g. Taking the specific heat of water as J/gC, the gross calorific value of the fuel is approximately:

determination of calorific value Hard
A. kJ/g
B. kJ/g
C. kJ/g
D. kJ/g

42 A fuel contains hydrogen by mass. Its gross calorific value is cal/g. Given the latent heat of steam is cal/g, the net calorific value is closest to:

determination of calorific value Hard
A. cal/g
B. cal/g
C. cal/g
D. cal/g

43 In the proximate analysis of coal, a g air-dried sample loses g on heating at , loses a further g on heating at (covered), and leaves g ash after burning. The percentage of fixed carbon is:

analysis of coal Hard
A.
B.
C.
D.

44 Which statement correctly distinguishes ultimate analysis from proximate analysis of coal?

analysis of coal Hard
A. Ultimate analysis gives elemental composition (C, H, N, S, O) while proximate analysis gives moisture, volatile matter, ash, and fixed carbon
B. Proximate analysis determines sulphur and nitrogen while ultimate analysis determines fixed carbon
C. Both give the same data but ultimate analysis uses a bomb calorimeter
D. Ultimate analysis gives moisture and ash while proximate analysis gives elemental composition

45 During discharge of a Ni-Cd cell, the reactions are and . Which conclusion about the electrolyte concentration is correct?

Ni-Cd Hard
A. Net concentration stays essentially constant since it is consumed at one electrode and produced at the other
B. is consumed overall, so electrolyte concentration falls sharply
C. is produced overall, raising the electrolyte concentration
D. Water is the net product, diluting the electrolyte continuously

46 A key advantage of Ni-MH batteries over Ni-Cd batteries, apart from being cadmium-free, is that:

Ni-metal hydride battery Hard
A. They offer higher energy density and reduced memory effect using a hydrogen-absorbing alloy negative electrode
B. They use a molten salt electrolyte enabling higher operating temperature
C. They are non-rechargeable and thus safer to dispose
D. They deliver a nominal cell voltage of V

47 In a Li-ion cell with a cathode and graphite anode, during charging the correct movement of lithium is:

Li-ion battery Hard
A. deintercalates from and intercalates into graphite
B. is oxidized to at the anode
C. Metallic Li is plated on the cathode while dissolves
D. deintercalates from graphite and intercalates into

48 Why is metallic lithium generally avoided as the anode in commercial rechargeable Li-ion cells despite its high specific capacity?

Li-ion battery Hard
A. Lithium metal has a higher reduction potential than graphite
B. Lithium metal reacts with the cathode to form only during discharge
C. Repeated cycling promotes dendrite growth that can cause internal short circuits
D. Metallic lithium cannot conduct electrons at room temperature

49 The overall discharge reaction of a lead-acid cell is . As the cell discharges, the specific gravity of the electrolyte:

Lead storage battery Hard
A. Remains constant, since sulphate is recycled
B. Decreases, because is consumed and water is produced
C. Increases, because water is consumed at the anode
D. Increases, because dissolves into the electrolyte

50 A V lead-acid battery is built from series-connected cells. Given each cell has a nominal EMF of about V, and the standard EMF arises from cathode ( V) and anode ( V), the number of cells and theoretical cell EMF are:

Lead storage battery Hard
A. cells, V each
B. cells, V each
C. cells, V each
D. cells, V each

51 The Li-air battery attracts research interest primarily because:

Li-air battery Hard
A. It produces no discharge product at the cathode
B. It uses cheap lead electrodes with an aqueous acid
C. It operates without any electrolyte, eliminating leakage
D. Its theoretical specific energy approaches that of gasoline since oxygen is drawn from air rather than stored

52 A major technical challenge limiting practical non-aqueous Li-air batteries is that the discharge product :

Li-air battery Hard
A. Is highly conductive and short-circuits the cell
B. Is insoluble and insulating, clogging the porous cathode and causing high overpotential
C. Is a gas that escapes, reducing coulombic efficiency
D. Dissolves the lithium anode instantly

53 Two fuels A and B have the same gross calorific value per kilogram. Fuel A contains significantly more hydrogen than fuel B. Which fuel has the higher net calorific value and why?

Calorific value of fuels Hard
A. Both equal, since GCV is identical
B. Fuel A, because water condensation adds to its usable heat
C. Fuel B, because less hydrogen means less water formed and lower latent heat loss
D. Fuel A, because hydrogen combustion releases extra heat

54 Which characteristic fundamentally distinguishes a primary cell from a secondary cell at the electrochemical level?

Primary cells Hard
A. Primary cells produce AC while secondary cells produce DC
B. Primary cells store more total energy than any secondary cell
C. Primary cells always use aqueous electrolytes while secondary cells use molten salts
D. In primary cells the electrode reactions are not readily reversible by charging, so they cannot be efficiently recharged

55 A secondary battery has an energy efficiency defined as . If a cell is charged at an average V and discharged at an average V with a coulombic (charge) efficiency of , its energy efficiency is closest to:

Secondary batteries Hard
A.
B.
C.
D.

56 In an - alkaline fuel cell, the anode reaction is and the cathode reaction is . A distinctive thermodynamic advantage of the fuel cell over a heat engine burning the same is that:

Fuel cells- principles, applications, advantages/disadvantages Hard
A. Its efficiency increases without bound as temperature falls
B. It produces that can be captured for extra energy
C. It stores reactants internally like a battery, needing no fuel supply
D. It is not limited by the Carnot efficiency, converting chemical energy directly to electrical energy

57 For an - fuel cell, kJ/mol and kJ/mol for water formation. The maximum theoretical (thermodynamic) efficiency of the cell is:

Fuel cells- principles, applications, advantages/disadvantages Hard
A.
B.
C.
D.

58 "Green hydrogen" is distinguished from "grey hydrogen" chiefly by:

hydrogen energy (production, storage, safety aspects) and significance as a clean and sustainable energy carrier Hard
A. Production via electrolysis of water using renewable electricity, with no net emission
B. Being produced by steam reforming of methane without a catalyst
C. Being stored at higher pressure in steel cylinders
D. Having a green colorant added for safety identification

59 In the fission of , about MeV is released per fission. Given eV J and Avogadro's number /mol, the energy released by complete fission of mole ( g) of is closest to:

nuclear energy (principles of nuclear energy, sustainable energy production) Hard
A. J
B. J
C. J
D. J

60 Spintronic devices differ from conventional electronics because they exploit:

spintronics and its engineering applications Hard
A. Only the mass of the electron to store data
B. Photon polarization instead of electrons
C. The electron's spin (magnetic moment) in addition to its charge, as seen in giant magnetoresistance read heads
D. The nuclear spin of the semiconductor lattice for conduction
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