Chemical Cells & Fuel Cells (Edexcel GCSE Chemistry)

Exam Questions

58 mins12 questions
1a2 marks

A fuel cell is an electrochemical cell.Ā 

Complete the sentences below using two words from the box.

Ā  ElectronĀ  Ā  ResistanceĀ  Ā 
ElectrodeĀ  Ā  Voltage Ā  Proton

A fuel donates electrons at one .......................... and oxygen gains electrons at the other electrode.

As the fuel enters the cell it becomes oxidised which sets up aĀ potential difference or ...................... within the cell
1b1 mark

The overall reaction in a hydrogen oxygen fuel cell forms water. Balance the equation for this reaction.


2H2 +Ā  O2 ā†’ ......... H2O

1c2 marks

Which of the following are advantages of using fuel cells in cars? Tick two boxes.

Quieter so less noise pollution than petrol and diesel cars

Ā 

They are efficient at a low temperatures

Ā 

No batteries to dispose of which is better for the environment

Ā 

Hydrogen is easy to store

Ā 
Ā 
1d2 marks

Which of the following are disadvantage of using fuel cells? Tick two boxes.

Materials used in producing fuel cellsĀ areĀ expensive

Ā 

Fuel cells emit pollutantsĀ 

Ā 

High pressureĀ tanks are dangerous and difficult to handle

Ā 

There are lots of moving parts meaning that energy is lost in transition

Ā 
Ā 

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2a3 marks

Figure 1 shows a simple cell containing a copper and zinc electrodes. Zinc is a more reactive metal than zinc.Ā 

Label the cell in Figure 1.

5-4-2a-e-electrochemical-cell-2a

2b2 marks

Higher only

The zinc electrode loses electrons and the copper electrode gains electrons. State the names of these processes.

Ā Ā Ā Loss of electrons is ..................

Ā Ā Ā Gain of electrons is ...................

2c1 mark

Another electrochemical cell was set up. Magnesium and silver were used as the electrodes.

Draw an arrow on Figure 2 to show the direction in which the electrons move in the solution.

5-4-2c-e-electrochemical-cell-2c-a5-4-2c-e-electrochemical-cell-2c-a

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3a1 mark

Hydrogen is a fuel that can be used instead of fossil fuels.Ā 

Which statement about fuels is true?

Ā  ā˜ A Fuels must produce no waste gases when they burn
Ā  ā˜ B Fuels must burn slowly
Ā  ā˜ C Fuels must be liquids at room temperature
Ā  ā˜ D Fuels must produce heat energy when they burn
3b1 mark

Write the word equation for the reaction between hydrogen and oxygen.

3c1 mark

Give one advantage of using a fuel cell instead of petrol to power a car.

3d1 mark

Which statement is a disadvantage of using a fuel cell instead of petrol to power a car?

Ā  ā˜ A Hydrogen is difficult to storeĀ 
Ā  ā˜ B Hydrogen is easy to transport
Ā  ā˜ C Hydrogen is a renewable resource
Ā  ā˜ D Hydrogen is cheap to produceĀ 

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1
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1 mark

Hydrogen fuel cells can be used to power trains.

Why could people refer to the hydrogen fuel cell trains as the 'new' steam trains?

Ā  ā˜ A The hydrogen used is extracted from fossil fuels
Ā  ā˜ B The hydrogen fuel cell trains are slower than diesel trains
Ā  ā˜ C The reaction produces water that can be released as steam
Ā  ā˜ D The reaction in the fuel cell is a combustion reaction

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21 mark

Hydrogen fuel cells are often used instead of rechargeable batteries in spacecraft.

Which of the following is not an advantage of using hydrogen fuel cells in spacecraft?

Ā  ā˜ A Water is the only product made in the reaction
Ā  ā˜ B Fuel cells operate as long as reactants are supplied
Ā  ā˜ C Hydrogen and oxygen are easily made by electrolysis of water
Ā  ā˜ D Hydrogen fuel cells are cheap

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3a1 mark

Hydrogen and oxygen are reactants in some fuel cells.

Which word equation shows the overall reaction that occurs in these fuel cells?

Ā  ā˜ A hydrogen + oxygen ā†’ hydroxide
Ā  ā˜ B hydrogen + oxygen ā†’ sulfuric acid
Ā  ā˜ C hydrogen + oxygen ā†’ water
Ā  ā˜ D hydrogen + oxygen ā†’ hydrochloric acid

3b2 marks

A torch contains a chemical cell.

The torch is turned on and then left on for many hours.

Describe what you would happen when the torch is turned on and then left for many hours.

3c1 mark

A chemical cell can be made by placing two metals into an electrolyte.

Figure 3 shows how the voltage of a simple chemical cell can be measured.

fig-3-q3c-1cho-1f-paper-1-nov-2021

Figure 3

A student investigated how the voltage of this cell was affected by the metal used for the rods.

Which is the only variable that should be changed in the investigation?

Ā  ā˜ A the size of the beaker
Ā  ā˜ B the element used for rod P
Ā  ā˜ C the concentration of the electrolyte
Ā  ā˜ D the temperature of the electrolyte

3d4 marks
Ā i)
Ā Explain why covering iron tools with a thin layer of grease prevents rusting.
(2)
ii)
Sacrificial protection is another way of preventing rusting.

An example of sacrificial protection is when lumps of zinc are connected to the iron-containing structure of an oil rig.
Explain how the zinc protects the iron from rusting.

(2)

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41 mark

Hydrogen fuel cells can be used in lorries and cars.

Which of the following is a potential disadvantage of using hydrogen fuel cells instead of petrol in a car?

Ā  ā˜ A Fuel cells are quieter than combustion engines
Ā  ā˜ B Fuel cells are smaller than combustion engines
Ā  ā˜ C Fuel cells have no moving parts
Ā  ā˜ D Water is the only product from the reaction

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51 mark

Hydrogen can be used in a hydrogen-oxygen fuel cell.Ā 

What does this cell produce?

Ā  ā˜ A Water and carbon dioxideĀ 
Ā  ā˜ B Water only
Ā  ā˜ C Carbon dioxide only
Ā  ā˜ D Hydrogen peroxideĀ 

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61 mark

Some batteries are examples of non rechargeable cells.Ā 

Why do these batteries eventually go flat?

Ā  ā˜ A The reaction is reversibleĀ 
Ā  ā˜ B The rate of reaction decreasedĀ 
Ā  ā˜ C An equilibrium has been established
Ā  ā˜ D One of the reactants is used up

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1a
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5 marks

Higher OnlyĀ 

Methane reacts with steam to form hydrogen and carbon dioxide.

The reaction takes place in two stages.

stage 1: CH4 (g) + H2O (g) rightwards harpoon over leftwards harpoon3H2 (g) + CO (g)
stage 2: CO (g) + H2O (g) rightwards harpoon over leftwards harpoonH2 (g) + CO2 (g)

i)
Stage 1 takes in heat energy, it is endothermic.

Explain the effect of increasing the temperature on the yield of the products of stage 1.
(2)
ii)
The overall equation for the process is

CH4 (g) + 2H2O (g) ā†’ 4H2 (g) + CO2 (g)

0.40 g of methane were fully reacted with steam to form carbon dioxide and hydrogen.

Calculate the maximum volume of hydrogen in dm3, measured at room temperature and pressure, that could be made in this reaction.

(relative formula mass: CH4 = 16,
1 mol of any gas at room temperature and pressure occupies 24 dm3)
(3)
maximum volume of hydrogen = ............................... dm3
1b6 marks

Hydrogen-oxygen fuel cells can be used to provide electrical energy in a spacecraft.

The reaction that takes place in the fuel cell is

hydrogen + oxygen ā†’ water

Evaluate the advantages and disadvantages of providing electrical energy in a spacecraft using hydrogen-oxygen fuel cells rather than chemical cells.

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2a1 mark

A fuel cell produces electrical energy by the oxidation of a fuel by oxygen.
The fuel is usually hydrogen but methane and methanol are two other fuels which may be used.
A diagram of a hydrogen fuel cell is given below in Figure 1.

hydrogen-fuel-cell

Figure 1

When the fuel is hydrogen, the hydrogen is oxidised to form water, which is the only product.

Suggest what additional product would be formed if methane was used.

2b1 mark

Write the chemical equation for the chemical reaction that takes place in a hydrogen fuel cell.

2c2 marks

Higher Only

In a hydrogen fuel cell, hydrogen loses electrons at the anode.

Write the half equation to show the reaction at the anode.

2d
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3 marks

Higher Only

Hydrogen and oxygen can also react in a combustion reaction forming water vapour.

Calculate the mass of water vapour produced when 500 cm3 of hydrogen combusts in excess oxygen.

Mass of water vapour ...................................... (g)

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3a2 marks

Electrolysis and chemical cells involve both electricity and chemical reactions.Ā 

Explain the difference between the processes in a chemical cell and electrolysis.Ā 

3b2 marks

Higher Only

In a hydrogen-oxygen fuel cell, hydrogen is oxidised at the anode.Ā 

Write the half-equation for this reaction.Ā 

3c6 marks

Hydrogen is used an alternative to petrol as a fuel in car engines.Ā 

Evaluate the advantages and disadvantages of using hydrogen rather than petrol as a fuel for cars.Ā 

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