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Ethanol can be made from plants and from crude oil as shown in Figure 6 - AQA - GCSE Chemistry - Question 4 - 2016 - Paper 1
Question 4
Ethanol can be made from plants and from crude oil as shown in Figure 6. **Figure 6** Plants Crude oil Sugar Alkanes Solution of sugar... show full transcript
Worked Solution & Example Answer:Ethanol can be made from plants and from crude oil as shown in Figure 6 - AQA - GCSE Chemistry - Question 4 - 2016 - Paper 1
Step 1
Describe how the solution of sugar in water is used to produce the mixture of ethanol and water.
Answer
To produce a mixture of ethanol and water from a solution of sugar in water, yeast is added to the sugar solution. The yeast ferments the sugar, converting it into ethanol and carbon dioxide. This reaction occurs in a warm environment, typically between 20-45 °C, and requires an absence of air to maximize ethanol production.
Step 2
Describe how ethanol is produced from ethene.
Answer
Ethanol is produced from ethene through a process called hydration. In this process, ethene is reacted with steam in the presence of a catalyst, such as phosphoric acid. The addition of water to the ethene molecule results in the formation of ethanol.
Step 3
Explain one advantage and one disadvantage of using crude oil to make ethanol instead of using plants.
Answer
One advantage of using crude oil is that it is a reliable source of ethanol, as crude oil supplies are stable and not subject to weather conditions or agricultural impacts. A disadvantage is that crude oil is a non-renewable resource. This means that its use is limited, and it contributes to environmental issues such as global warming if used excessively.
Step 4
Describe how distillation is used to separate a mixture of ethanol and water.
Answer
Distillation is used to separate ethanol from water based on their different boiling points. Ethanol has a boiling point of 78 °C, while water boils at 100 °C. When the mixture is heated, ethanol will evaporate at a lower temperature. The vapors can then be condensed back into liquid form, effectively separating ethanol from water, as the water remains in the distillation apparatus until it reaches a higher temperature.