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Question
Find the number of molecules in 1.8 g of H2O.
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Solution
Molecular weight of water = H2O
= (1 × 2) + 16
= 18 g
18 g of H2O has molecules = 6.02 x 1023
∴ 1.8 g of H2O has molecules = `(6.02 xx 10^(23))/18 xx 1.8`
= 6.02 × 1022
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