SOF National Science Olympiad (NSO/ISO)
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NSO Level 1
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2024
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Sample
Plaster of Paris is chemically known as which of the following?
Explanation
Explanation
Plaster of Paris (CaSO4·½H2O) is obtained by heating gypsum (CaSO4·2H2O) at 373 K, and it sets into a hard mass on mixing with water, which is why it's used for casts and moulds.
PRO TIP
Re-check your working by substituting the answer back into the original question.
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