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Table 21.1 shows information about four different substances - OCR Gateway - GCSE Chemistry - Question 21 - 2023 - Paper 3
Question 21
Table 21.1 shows information about four different substances. | Substance | Melting point (°C) | Appearance | Electrical conductor? | |-----------|-... show full transcript
Worked Solution & Example Answer:Table 21.1 shows information about four different substances - OCR Gateway - GCSE Chemistry - Question 21 - 2023 - Paper 3
Step 2
Explain your answer. Reason
Answer
Substance 3 is classified as a polymer because it is a flexible solid, which indicates that it consists of long chains of repeating units (monomers). This characteristic is typical of polymers, which generally have lower melting points compared to metals and can exhibit flexibility.
Step 3
Explain why polymers without cross-links can stretch more than polymers with cross-links.
Answer
Polymers without cross-links can stretch more than those with cross-links because the absence of cross-links allows the polymer chains to slide over each other more easily. In contrast, cross-links create bonds between the chains that limit their ability to move independently. This restriction leads to a more rigid structure that cannot stretch as effectively.