AQA · A-Level · Chemistry
Course version: 7405 · Version from Sept 2016
The benefits and risks to society associated with using these cells.
Full specification wording
Commercial applications of electrochemical cells (A-level only): The benefits and risks to society associated with using these cells.
Judging a cell means looking beyond the device itself.
Checked against the AQA 7405 specification (opens in a new tab) on .
- Point 4 of 5
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Judging a cell means looking beyond the device itself. The benefits are portable, reliable power; fuel cells release only water at the point of use, so no carbon dioxide or particulates enter a city street; rechargeable cells reduce the number of cells thrown away. The risks are real too. Cells contain toxic or corrosive materials, including cadmium, lithium compounds and concentrated alkali, which can leach from landfill into groundwater; lithium cells can catch fire if damaged or overcharged; hydrogen is extremely flammable and is stored at very high pressure. There is also the wider accounting: most hydrogen is made from methane, so the carbon dioxide appears at the plant rather than the exhaust, and mining lithium and cobalt carries its own environmental and human cost.
What earns the marks
- A named benefit, such as only water being released at the point of use.
- A named risk, such as the flammability of hydrogen or the toxicity of a metal in the cell.
- Referring to how the hydrogen or the electricity was produced, rather than only the cell itself.
- A conclusion that weighs the stated benefit against the stated risk.
Common mistakes and how to put them right
Writing 'better for the environment' with no named substance or effect.
Ignoring that hydrogen is usually manufactured from methane, so carbon dioxide is still released elsewhere.
Treating the disposal of lithium or cadmium cells as harmless.
Listing only advantages when the command word is 'evaluate' or 'discuss'.
Exam tips
- Name a specific substance in every point; 'chemicals leak out' scores nothing, 'cadmium leaches into groundwater' scores.
- An evaluation needs a stated conclusion at the end, not just a list of two columns.
Try the lesson
The start of the Commercial applications of electrochemical cells (A-level only): The benefits and risks to society associated with using these cells. lesson, made from checked teaching notes for this specification point.
Have a go first
Which of the following is a benefit to society of using non-rechargeable cells in portable devices?
Listen
Judging a cell means looking beyond the device itself. The benefits are portable, reliable power; fuel cells release only water at the point of use, so no carbon dioxide or particulates enter a city street; rechargeable cells reduce the number of cells thrown away. The risks are real too. Cells contain toxic or corrosive materials, including cadmium, lithium compounds and concentrated alkali, which can leach from landfill into groundwater; lithium cells can catch fire if damaged or overcharged; hydrogen is extremely flammable and is stored at very high pressure. There is also the wider accounting: most hydrogen is made from methane, so the carbon dioxide appears at the plant rather than the exhaust, and mining lithium and cobalt carries its own environmental and human cost. A strong answer earns marks for these points. a named benefit, such as only water being released at the point of use. a named risk, such as the flammability of hydrogen or the toxicity of a metal in the cell. referring to how the hydrogen or the electricity was produced, rather than only the cell itself. a conclusion that weighs the stated benefit against the stated risk. Exam tip: Name a specific substance in every point; 'chemicals leak out' scores nothing, 'cadmium leaches into groundwater' scores.
See it
Key words
Say what each word means before you turn the card.
risk and benefit
Try answering aloud or in your head before turning the card.
disposal and toxicity
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hydrogen flammability
Try answering aloud or in your head before turning the card.
upstream emissions
Try answering aloud or in your head before turning the card.
See every definition
- risk and benefit
- The risks and benefits to society associated with using electrochemical cells, which must be weighed against each other in an evaluation.
- disposal and toxicity
- Cells contain toxic or corrosive materials, including cadmium, lithium compounds and concentrated alkali, which can leach from landfill into groundwater.
- hydrogen flammability
- Hydrogen is extremely flammable and is stored at very high pressure.
- upstream emissions
- Most hydrogen is made from methane, so the carbon dioxide appears at the plant rather than the exhaust.
Label the diagram
Some boxes have lost their names. Pick the right name for each number.
1Box 1
2Box 2
3Box 3
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