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Bromine is a liquid at room temperature and vaporises readily - Edexcel - GCSE Chemistry - Question 8 - 2022 - Paper 1
Question 8
Bromine is a liquid at room temperature and vaporises readily. Bromine has a simple molecular structure. (b) Part of the structure of graphene is shown in Figure 5.... show full transcript
Worked Solution & Example Answer:Bromine is a liquid at room temperature and vaporises readily - Edexcel - GCSE Chemistry - Question 8 - 2022 - Paper 1
Step 1
Explain why graphene will be a good conductor of an electric current.
Answer
Graphene is composed of carbon atoms arranged in a hexagonal lattice structure. This structure allows for a delocalization of electrons, meaning that the electrons are not bound to any particular atom and can move freely throughout the material. The high mobility of these electrons enables graphene to efficiently conduct electric current, making it an excellent conductor.
Step 2
Explain why potassium chloride has a high melting point.
Answer
Potassium chloride (KCl) is an ionic compound composed of potassium ions (K⁺) and chloride ions (Cl⁻). The high melting point of KCl can be attributed to the strong electrostatic forces of attraction between the oppositely charged ions in the lattice structure. These ionic bonds are strong and require a significant amount of energy to break, which contributes to the high melting point of 770°C.
Step 3
Describe what information can be obtained from each representation including the limitations of these representations of methane.
Answer
Representation A (CH₄) shows the molecular formula indicating the ratio of carbon to hydrogen atoms. Representation B (ball and stick model) provides a 3D visualization of the molecular shape and bond angles. Representation C (structural formula) illustrates the connectivity between atoms. However, it oversimplifies electron distribution. Representation D (dot-and-cross diagram) shows bonding as well as the arrangement of outer shell electrons, emphasizing electron sharing. Representation E (space-filling model) displays the relative sizes of atoms and overall geometry. However, it does not accurately depict bond angles or show individual bonds distinctly. Each representation has its strengths and limitations, failing to convey comprehensive information regarding bond properties and arrangement in real molecular dynamics.