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

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]

Tutorialspoint

Simply Easy Learning

Updated on: 19-Jan-2023

15 Views

Kickstart Your Career

Get certified by completing the course

Get Started