Photo AI
The concentration of carbon dioxide (CO₂) in the Earth’s atmosphere has been increasing steadily since the mid nineteenth century - VCE - SSCE Chemistry - Question 5 - 2002 - Paper 1
Question 5
The concentration of carbon dioxide (CO₂) in the Earth’s atmosphere has been increasing steadily since the mid nineteenth century. This is due mainly to the increase... show full transcript
Worked Solution & Example Answer:The concentration of carbon dioxide (CO₂) in the Earth’s atmosphere has been increasing steadily since the mid nineteenth century - VCE - SSCE Chemistry - Question 5 - 2002 - Paper 1
Step 1
i. Name one factor, other than the heat of combustion, that should be considered when selecting a fuel for a particular purpose.
Answer
One key factor to consider when selecting a fuel is its energy content. This is crucial because it dictates the amount of energy that can be obtained from a specific volume or mass of fuel, impacting efficiency and fuel choice for various applications.
Step 2
ii. The burning of fossil fuels is associated with other undesirable emissions besides CO₂. Give two other undesirable atmospheric pollutants directly or indirectly caused by the burning of fossil fuels.
Answer
Two notable atmospheric pollutants include:
- Sulfur Dioxide (SO₂): Emitted during the combustion of fossil fuels like coal, it can contribute to acid rain.
- Nitrogen Oxides (NOₓ): Produced from burning fossil fuels at high temperatures, these gases are key contributors to air pollution and smog formation.
Step 3
Choose any two of the following non-fossil fuels alternatives.
Answer
-
Nuclear
- Advantage: Nuclear energy can provide major energy output with a small fuel requirement.
- Disadvantage: The disposal of nuclear waste remains a significant environmental challenge.
-
Solar
- Advantage: Solar energy is renewable and inexhaustible, available in abundance without emissions during operation.
- Disadvantage: The production of solar panels can be resource-intensive and energy-consuming.
Step 4
i. What is meant by the term ‘nuclear fission’?
Answer
Nuclear fission is a process where the nucleus of an atom splits into two or more smaller nuclei, along with the release of a significant amount of energy. This reaction commonly occurs in heavy isotopes like uranium-235 when bombarded by neutrons.
Step 5
ii. What is the source of the energy released when ²³⁵U undergoes fission?
Answer
The energy released during the fission of ²³⁵U primarily comes from the conversion of mass into energy, as described by Einstein's equation, . The splitting of the nucleus results in a loss of mass, which is released as energy.