Photo AI
The formula of a molecule of ethanol is C₂H₅OH - Edexcel - GCSE Chemistry - Question 6 - 2016 - Paper 1
Question 6
The formula of a molecule of ethanol is C₂H₅OH. (i) State how you know, from its formula, that ethanol is not a hydrocarbon. (ii) A dilute solution of ethanol can ... show full transcript
Worked Solution & Example Answer:The formula of a molecule of ethanol is C₂H₅OH - Edexcel - GCSE Chemistry - Question 6 - 2016 - Paper 1
Step 1
State how you know, from its formula, that ethanol is not a hydrocarbon.
Answer
Ethanol contains oxygen atoms in its formula (C₂H₅OH), while hydrocarbons are organic compounds that consist only of carbon and hydrogen atoms. Therefore, the presence of oxygen indicates that ethanol is not a hydrocarbon.
Step 2
A dilute solution of ethanol can be produced by the fermentation of a carbohydrate. Starting from sugar (a carbohydrate), describe how a dilute solution of ethanol can be produced.
Answer
To produce a dilute solution of ethanol from sugar, follow these steps:
- Dissolve the sugar in warm water. This creates a sugar solution.
- Add yeast to the sugar solution. Yeast will ferment the sugar to produce ethanol and carbon dioxide.
- Leave the mixture in a warm place to allow fermentation to occur.
- Ensure the vessel is covered with an airlock or cotton wool to allow gases to escape while preventing contamination.
Step 3
Step 5
Name and draw the structures of some alkanes and of some alkenes and use them to show how members of a homologous series are similar in their general formula, names and structures of their molecules.
Answer
Alkanes and alkenes are examples of homologous series where:
-
Alkanes are saturated hydrocarbons with the general formula CₙH₂ₙ₊₂.
- Methane: CH₄
- Ethane: C₂H₆
- Propane: C₃H₈
- Butane: C₄H₁₀
-
Alkenes are unsaturated hydrocarbons with the general formula CₙH₂ₙ.
- Ethene: C₂H₄
- Propene: C₃H₆
Each successive member of these series differs by a -CH₂- unit, showing their similarity in general structure.