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Question
Deduce the number of molecules of the following compound in the given quantity.
90g water
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Solution
Number of moles in water = `"Mass of water in grams"/"Molecular mass of water"`
= `90/18`
= 5 moles
∴ 5 moles of H2O contains = 5 × 6.022 × 1023 molecules = 30.11 × 1023 molecules.
The number of molecules in 90 grams of water is 3.01 × 1024.
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