Question

$2.0g$ of oxygen contains number of atoms equal to that in:

• A. 4.0 g of sulphur
• B. 7.0 g of nitrogen
• C. 0.5 g of hydrogen
• D. 2.3 got sodium

Answer 1

Answer: (A)

Number of atoms in $1g$ of an element $=\frac{6.023\times 10^{23}}{\text{ atomic mass }}$
$\therefore$ Number of atoms in $2g$ of oxygen $=\frac{6.023\times 10^{23}\times 2}{16}$
$=\frac{6.023\times 10^{23}}{8}$
and number of atoms in $4g$ of sulphur
$=\frac{6.023\times 10^{23}\times 4}{32}$
$=\frac{6.023\times 10^{23}}{8}$