Which of the following has maximum number of atoms?
(a) 18g of H2O
(b) 18g of O2
(c) 18g of CO2
(d) 18g of CH4

AcademicChemistryNCERTClass 9

Correct Answer: (d) 18g of CH4

Explanation: Number of atoms = Mass of substance × Number of atoms in the molecule/ Molar mass × NA

18 g of water =18 x3/18 ×NA = 3 NA

18 g of oxygen = 18 x2 /32 × NA = 1.12 NA

18 g of CO2 = 18 x3/44 × NA = 1.23 NA

18 g of CH4 =18 x5 /16 × NA = 5.63 NA

[Note: NA = 6.023×1023]

raja
Updated on 10-Oct-2022 13:30:05

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