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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 ... 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, thus not adding extra carbon dioxide 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 dissolves in water, while the hydrophobic tail dissolves in oil. This creates a stable mixture where tiny droplets of oil are dispersed in water, preventing separation.
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
When plant oils react with hydrogen at 60 °C in the presence of a nickel catalyst, hydrogen adds to the carbon-carbon double bonds in the oils. This process opens up the double bonds, transforming unsaturated oils into more saturated oils, often resulting in a solid or semi-solid product.