Which one of the following could be the melting point of iron?
- A.25°C
- B.37°C
- C.500°C
- D.1500°C
Correct answer
Explanation
The correct answer is D, 1500°C. Pure iron melts at about 1,538°C, so 1,500°C is the only option close to its melting point.
Iron is a metal with strong metallic bonds, so a great deal of heat is needed to break up its solid structure. This is why iron ore is smelted in a blast furnace, where temperatures go well above 1,500°C. Most metals have high melting points, though there are exceptions: mercury is a liquid at room temperature, and gallium and caesium melt at around 30°C, so gallium can melt in the palm of the hand. Tungsten has the highest melting point of all metals, about 3,422°C, which is why it is used in bulb filaments.
A is wrong because 25°C is about room temperature, at which iron is clearly a solid.
B is wrong because 37°C is normal human body temperature.
C is wrong because 500°C is far too low; iron only glows red at that temperature and stays solid.
Exam tip: iron melts at about 1,538°C, tungsten at about 3,422°C; mercury is the only metal liquid at room temperature.
Practice Questions
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- D.Collenchyma
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- B.symport
- C.uniport
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- A.water
- B.carbon dioxide
- C.oxygen
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- A.Epithelial tissue
- B.Muscular tissue
- C.Nervous tissue
- D.Connective tissue
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