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6 (a) Explain one advantage of using biodiesel made from plant oils compared with using fossil diesel made from crude oil - AQA - GCSE Chemistry - Question 6 - 2017 - Paper 1
Question 6
6 (a) Explain one advantage of using biodiesel made from plant oils compared with using fossil diesel made from crude oil. 6 (b) Plant oils are used in emulsions to... show full transcript
Worked Solution & Example Answer:6 (a) Explain one advantage of using biodiesel made from plant oils compared with using fossil diesel made from crude oil - AQA - GCSE Chemistry - Question 6 - 2017 - Paper 1
Step 1
Explain one advantage of using biodiesel made from plant oils compared with using fossil diesel made from crude oil.
Answer
Biodiesel is carbon neutral because it releases the carbon dioxide that was absorbed by the plants during photosynthesis. This means that while using biodiesel, no extra carbon dioxide is added to the atmosphere.
Step 2
Explain how an emulsion of water and oil is formed.
Answer
An emulsion is formed when an emulsifier is added to a mixture of water and oil. The hydrophilic head of the emulsifier molecule dissolves in the water, while the hydrophobic tail dissolves in the oil. This creates stable droplets of oil in water (or vice versa), resulting in a consistent texture.
Step 3
Step 4
Describe and explain what happens to plant oils when they react with hydrogen in the presence of a nickel catalyst at about 60 °C.
Answer
During this reaction, hydrogen adds to the carbon-carbon double bonds in the unsaturated oils, resulting in the oils becoming more saturated. This process can increase the melting point of the oils, making them solid or semi-solid at room temperature.