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This question is about hydrocarbons and crude oil - AQA - GCSE Chemistry Combined Science - Question 7 - 2019 - Paper 2
Question 7
This question is about hydrocarbons and crude oil. 07.1 Hydrocarbon fuels are produced from crude oil. Describe how crude oil is separated into fractions. 07.2 Bu... show full transcript
Worked Solution & Example Answer:This question is about hydrocarbons and crude oil - AQA - GCSE Chemistry Combined Science - Question 7 - 2019 - Paper 2
Step 1
Describe how crude oil is separated into fractions.
Answer
Crude oil is separated into fractions using a process called fractional distillation. This involves heating the crude oil in a distillation column where it vaporizes. The vapor rises through the column, which has a temperature gradient; it is cooler at the top and hotter at the bottom. As the vapor ascends, it cools and condenses into different fractions depending on their boiling points, allowing for separation at various levels within the column.
Step 2
Why are different products formed?
Answer
Different products are formed due to the varying amounts of oxygen available during combustion. When there is a sufficient supply of oxygen, complete combustion occurs, resulting in carbon dioxide and water. Conversely, when oxygen is limited, incomplete combustion takes place, producing carbon monoxide and other byproducts.
Step 4
Describe the greenhouse effect in terms of the interaction of short and long wavelength radiation with matter.
Answer
The greenhouse effect is caused by short wavelength radiation from the sun entering the Earth's atmosphere. This radiation is absorbed by the Earth's surface and is then re-emitted as long wavelength radiation. Greenhouse gases, such as carbon dioxide, trap this longer wavelength radiation within the atmosphere, preventing it from escaping back into space. This process leads to an increase in atmospheric temperature, contributing to global warming.