Question detail
Which of the following correctly describes an alkene?
Try the question, check the answer, then read the explanation to understand the curriculum point.
At a glance
MCQ
Type
practice
Style
Topic
Alkenes
Question
- A. A saturated hydrocarbon with single bonds only
- B. An unsaturated hydrocarbon containing at least one C=C bond
- C. A compound that can only form single bonds
- D. A hydrocarbon that contains only carbon and hydrogen atoms
Answer
An unsaturated hydrocarbon containing at least one C=C bond
Explanation
Alkenes are defined as unsaturated hydrocarbons because they contain at least one carbon-carbon double bond (C=C), which allows them to undergo addition reactions.
Common mistake
Misunderstanding Addition Polymerisation
Students often confuse addition polymerisation with condensation polymerisation, thinking they are the same process.
Addition polymerisation involves the repeated addition of alkene monomers across C=C bonds. To clarify, remember that in addition polymerisation, no small molecules are lost, while in condensation polymerisation, small molecules like water are released. For example, the polymerisation of ethene (C2H4) can be represented as: 1. **Rule**: Addition polymerisation occurs across C=C bonds. 2. **Substitution**: C2H4 → (C2H4)n 3. **Working**: Each C=C bond opens up to form a long chain of repeating units. 4. **Answer**: The repeat unit is -C2H4- 5. **Units/Conclusion**: This shows that addition polymerisation creates a polymer without the loss of any small molecules.
Related flashcards
Flashcard 1 of 6
Related practice questions
Question 1 of 5
Choose an answer, get feedback, then move sideways through the set.