Question

Which of the following contains greatest number of oxygen atoms ?

• A. $1\, g$ of $O$
• B. $1\, g$ of $ O_2 $
• C. $1\, g$ of $ O_3 $
• D. All have the same number of atoms

Answer 1

Answer: (D)

Number of atoms $=$ moles $\times N_{A} \times$ atomicity

Here, $N_{A}=$ Avogadro's number

(a) Number of oxygen atoms in $1 \,g$ of $O$

$=\frac{1}{16} \times N_{A} \times 1 $

$=\frac{N_{A}}{16}$

(b) Number of oxygen atoms in $1\, g$ of $O _{2}$

$=\frac{1}{32} \times N_{0} \times 2$

$=\frac{N_{A}}{16}$

(c) Number of oxygen atoms in $1\, g$ of $O _{3}$

$=\frac{1}{48} \times N_{A} \times 3=\frac{N_{A}}{16}$

Hence, all have the same number of oxygen atoms.