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19 Metal elements and non-metal elements have different physical properties - OCR Gateway - GCSE Chemistry - Question 19 - 2019 - Paper 3
Question 19
19 Metal elements and non-metal elements have different physical properties. The table shows the physical properties of some elements. Element Melting point (°C) ... show full transcript
Worked Solution & Example Answer:19 Metal elements and non-metal elements have different physical properties - OCR Gateway - GCSE Chemistry - Question 19 - 2019 - Paper 3
Step 1
Which element, A, B, C or D, would be best to use for cables in overhead pylons to transfer electricity? Tick (✓) one box.
Answer
The best element for cables in overhead pylons to transfer electricity is C. This is because it has a high melting point and high density, combined with good electrical and thermal conductivity. This combination of properties ensures that the cables will handle a significant amount of electrical current without overheating and will remain stable under environmental conditions.
Step 2
Explain your answer.
Answer
Element C is advantageous as it possesses high density and good electrical conductivity, making it suitable for transferring electricity. Its high melting point indicates that it can withstand high temperatures without breaking down, which is crucial for overhead cables that may experience heat during operation.
Step 3
What is meant by physical property?
Answer
A physical property refers to a characteristic of a substance that can be observed or measured without changing the substance's chemical identity. Examples include melting point, density, and conductivity, which describe how a material behaves under various physical conditions.
Step 4
Describe how you could test the oxide to find out if the element is a metal.
Answer
To test whether the oxide of element C indicates a metal, heat a sample of the oxide strongly, then react it with an acid such as hydrochloric acid (HCl). If the reaction produces hydrogen gas (H₂), then element C is likely a metal, as metals typically react with acids to release hydrogen. This can be confirmed by collecting the gas and testing it with a lit splint, which should produce a 'pop' sound if hydrogen is present.
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