Question

Number of atoms in 560 $cm^3$ of oxygen at S.T.P. is

• A. $\frac{1}{20} \times 6.022 \times 10^{23}$
• B. $\frac{1}{40} \times 6.022 \times 10^{23}$
• C. $\frac{1}{16} \times 6.022 \times 10^{23}$
• D. $\frac{1}{32} \times 6.022 \times 10^{23}$

Answer 1

Answer: (A)

$\frac{1}{20} \times 6.022 \times 10^{23}$

Answer 2

$22400 \, cm^3$ of oxygen $(O_2)$ at S.T.P.
= $2 \times 6.022 \times 10^{23}$ atoms
$560\, cm^3$ of oxygen at S.T.P.
= $\frac{2 \times 6.022 \times 10^{23} }{22400} \times 560$
= $\frac{1}{20} \times 6.022 \times 10^{23}$ atoms