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Complete combustion of 1.8 g of an oxygen-containing organic compound gave 2.64 g of CO ₂ and 1.08 g of H ₂ O . If the vapour density of the compound is 30 , the total number of atoms present in one molecule of the compound is

Correct answer

8

Step-by-step solution

Mass of carbon in the compound = 12 44 Mass of CO ₂ = 12 44 2.64 = 0.72 g Mass of hydrogen in the compound = 2 18 Mass of H ₂ O = 2 18 1.08 = 0.12 g Mass of oxygen in the compound = Total mass - (Mass of C + Mass of H) Mass of oxygen = 1.8 - (0.72 + 0.12) = 1.8 - 0.84 = 0.96 g Moles of C = 0.72 12 = 0.06 mol Moles of H = 0.12 1 = 0.12 mol Moles of O = 0.96 16 = 0.06 mol The molar ratio of C : H : O is 0.06 : 0.12 : 0.06 , which simplifies to 1 : 2 : 1 . The empirical formula is CH ₂ O . Empirical formula mass = 12

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