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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. Butane ... 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 through a process called fractional distillation. During this process, the crude oil is first heated or vaporized in a distillation column. This creates a temperature gradient in the column, with the heat being higher at the bottom and cooler at the top.
As the vapor rises, different hydrocarbons condense at various heights based on their boiling points, forming distinct fractions. Lighter substances with lower boiling points condense higher in the column, while heavier substances condense lower down.
Step 2
Why are different products formed?
Answer
Different products are formed during the combustion of butane due to varying amounts of oxygen available in the reaction. In situations with limited oxygen, incomplete combustion occurs, resulting in byproducts such as carbon monoxide (CO) instead of only carbon dioxide (CO₂) and water (H₂O). This leads to different combustion products being produced depending on the oxygen supply.
Step 3
Step 4
Describe the greenhouse effect in terms of the interaction of short and long wavelength radiation with matter.
Answer
The greenhouse effect occurs when short wavelength radiation from the sun enters the Earth's atmosphere and is absorbed by materials on the Earth's surface. This absorbed energy is re-emitted as long wavelength radiation.
However, the longer wavelength radiation is partially trapped by greenhouse gases like carbon dioxide (CO₂), which prevents heat from escaping back into the atmosphere. Consequently, this leads to an increase in Earth's temperature, contributing to global warming.