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Different car engines are designed to use different fuels - Edexcel - GCSE Chemistry - Question 4 - 2012 - Paper 1
Question 4
Different car engines are designed to use different fuels. These fuels include diesel, ethanol, hydrogen, LPG (liquefied petroleum gas) and petrol. (a) LPG contains ... show full transcript
Worked Solution & Example Answer:Different car engines are designed to use different fuels - Edexcel - GCSE Chemistry - Question 4 - 2012 - Paper 1
Step 1
Step 2
Describe how you would use limewater to show that carbon dioxide is produced.
Answer
To demonstrate that carbon dioxide is produced when propane burns:
- Mixing Carbon Dioxide: First, bubble the gas produced during the combustion of propane through limewater. This can be done by connecting a delivery tube from the combustion vessel to the limewater container.
- Observation of Precipitate: Upon passing the gas, observe the changes in the limewater. If carbon dioxide is present, the limewater will turn milky/cloudy due to the formation of calcium carbonate as a precipitate.
Step 3
Explain a problem caused by the products of this incomplete combustion.
Answer
Incomplete combustion of propane can lead to the formation of harmful products such as:
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Carbon Monoxide: This is a toxic gas that can pose health risks, as it binds to hemoglobin in the blood more effectively than oxygen, reducing oxygen delivery to vital organs, potentially leading to suffocation or death.
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Soot/Smoke: The incomplete combustion can also produce soot, which can dirty surfaces and create air quality problems, posing respiratory risks for individuals exposed.
Step 4
Step 5
Explain how a biofuel is different from a fossil fuel.
Answer
Biofuels are derived from recent biological materials, such as plants or animal waste, making them renewable and capable of being replenished over a short period of time. In contrast, fossil fuels are formed from the ancient remains of plants and animals buried and subjected to heat and pressure over millions of years, making them non-renewable and limited in availability.
Step 6
Explain which fuel, A or B, would be best for powering a car.
Answer
To determine the best fuel for powering a car between A and B, consider:
- Fuel A (Gas): It has a higher energy yield of 142 MJ per kg compared to Fuel B which provides only 47 MJ per kg. However, the availability is limited.
- Fuel B (Liquid): It costs less per kg but provides significantly less energy.
For optimal performance and efficiency in powering a car, Fuel A would likely be preferred due to its higher energy output despite its limited availability.