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Bromine is a liquid at room temperature and vaporises readily - Edexcel - GCSE Chemistry Combined Science - Question 5 - 2022 - Paper 1
Question 5
Bromine is a liquid at room temperature and vaporises readily. Bromine has a simple molecular structure. Which row of the table shows the most likely melting and bo... show full transcript
Worked Solution & Example Answer:Bromine is a liquid at room temperature and vaporises readily - Edexcel - GCSE Chemistry Combined Science - Question 5 - 2022 - Paper 1
Step 1
Which row of the table shows the most likely melting and boiling points of bromine?
Answer
Based on the molecular structure of bromine, which is a diatomic molecule (Br₂), the expected melting and boiling points are relatively low due to weak van der Waals forces between the molecules. The most appropriate row is B, with a melting point of -17 °C and a boiling point of 63.3 °C. This indicates the transitions from solid to liquid and liquid to gas at temperatures consistent with Br₂.
Step 2
Explain why graphene will be a good conductor of an electric current.
Answer
Graphene is an excellent conductor of electricity due to its unique structure. It is a single layer of carbon atoms arranged in a two-dimensional honeycomb lattice. This configuration allows electrons to move freely across the lattice with minimal resistance because:
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Delocalized Electrons: In graphene, each carbon atom is bonded to three others, using sp² hybridization, which leaves one electron free to move. This delocalization of electrons provides a high level of electrical conductivity.
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High Electron Mobility: The two-dimensional structure and strong bonds in graphene mean that electrons can travel through it very quickly, resulting in low resistivity.
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Large Surface Area: Graphene has a vast surface area, which can accommodate more charge carriers, enhancing its conductivity further.
These properties combined make graphene exceptionally conductive compared to other materials.