On the Mohs hardness scale used in mineral processing, which of the following is the softest material?
Chemical Engineering
Mechanical Operations
Difficulty: Easy
Choose an option
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ATalc
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BFeldspar
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CCorundum
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DCalcite
Answer
Correct Answer: Talc
Explanation
Introduction / Context:The Mohs scale ranks minerals by scratch resistance from 1 (softest) to 10 (hardest). Knowledge of hardness guides equipment selection and wear considerations in comminution.
Concept / Approach:On the Mohs scale: Talc = 1, Gypsum = 2, Calcite = 3, Feldspar ≈ 6, Corundum = 9. Therefore, talc is the softest listed mineral.
Why Other Options Are Wrong:Calcite: hardness 3.Feldspar: hardness ~6.Corundum: hardness 9 (very hard).
Final Answer:Talc