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Diamond and chlorine are both covalently bonded - OCR Gateway - GCSE Chemistry Combined Science - Question 15 - 2020 - Paper 1
Question 15
Diamond and chlorine are both covalently bonded. The table shows the melting points of two substances, X and Y. | Substance | Melting point (°C) | |-----------|---... show full transcript
Worked Solution & Example Answer:Diamond and chlorine are both covalently bonded - OCR Gateway - GCSE Chemistry Combined Science - Question 15 - 2020 - Paper 1
Step 1
Is the student correct?
Answer
The student is correct that substance X is diamond, but incorrect that substance Y is chlorine.
Explanation:
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Structure of Diamond: Diamond is a giant covalent structure where each carbon atom is tetrahedrally bonded to four other carbon atoms. This strong covalent bonding gives diamond an extremely high melting point of 3550 °C, which matches the melting point of substance X.
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Structure of Chlorine: Chlorine, on the other hand, is a simple molecular substance. It consists of diatomic molecules (Cl), where the molecules are held together by weaker van der Waals forces rather than strong covalent bonds. Thus, chlorine has a low melting point of -102 °C, which matches the melting point of substance Y.
In summary, the melting point indicates that substance X exhibits properties of diamond, while substance Y indicates properties of chlorine.