Chemical reactions can produce electricity.
Figure 2 shows a simple cell.
Figure 2
Which of these combinations would not give a zero reading on the voltmeter in Figure 2? [1 mark]
Tick one box.
ANSWER
Copper, Zinc, Sodium Chloride Solution
Alkaline batteries are non-rechargeable.
Why do alkaline batteries eventually stop working? [1 mark]
ANSWER
When the chemicals inside the cell are used up, alkaline batteries eventually stop.
Why can alkaline batteries not be recharged? [1 mark]
ANSWER
The chemical reactions inside the alkaline batteries cannot be reversed by passing an electric current through it.
Hydrogen fuel cells and rechargeable lithium-ion batteries can be used to power electric cars.
Complete the balanced equation for the overall reaction in a hydrogen fuel cell. [2 marks]
ANSWER
2H2 + O2 → 2H2O
Table 1 shows data about different ways to power electric cars.
Table 1
Evaluate the use of hydrogen fuel cells compared with rechargeable lithium-ion batteries to power electric cars.
Use Table 1 and your own knowledge. [6 marks]
ANSWER
Reasons why fuel cells could be considered as better
time for refueling a fuel cell is faster than recharging or a fuel cell does not need to be recharged
a fuel cell has a greater range
Additionally,
hydrogen can be renewable if made by electrolysis using renewable energy
lithium-ion batteries can catch fire
Produces only water or no pollutants produced • lithium-ion batteries may release toxic chemicals on disposal • lithium-ion batteries (eventually cannot be recharged so) have a finite life
Reasons why the lithium-ion battery could be considered as better
lithium-ion uses energy more efficiently
cost of lithium-ion car much less
cost of recharging much less than refuelling with hydrogen
Additionally,
Hydrogen is often made from fossil fuels so is not renewable
Charging points are more widely available than hydrogen filling stations
Hydrogen takes up a lot of space or is difficult to store
Hydrogen can be highly flammable / explosive
No emissions produced
Catalyst in the hydrogen fuel-cell eventually becomes poisoned so have a finite life
