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Question
Calculate the number of molecules in 4 g of oxygen.
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Solution
Mass of oxygen = 4g
We know that 32g of oxygen contain 6.022 × 1023 molecules.
Number of molecules in 32g of oxygen = 6.022 × 1023
Number of molecules in 4g of oxygen = 4 × 6.022 × 1023/32
Hence, 4g of oxygen have 7.52 × 1022 molecules.
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