Question

$2$ g of oxygen contains atoms equal to that in

• A. $0.5$ g of hydrogen
• B. $4$ g of sulphur
• C. $7$ g of nitrogen
• D. $2.3$ g of sodium

Answer 1

Answer: (B)

$4$ g of sulphur

$2$ g of oxygen $=\frac{2}{32}=\frac{1}{16}$ moles (M.w. of $O_2$ =32 g/mol)

$4$ g of sulphur $=\frac{4}{32\times 8}=\frac{1}{64}$ moles (M.w. of $S=32\times 8$ g/mol)

$\frac{1}{16}$ moles of oxygen has $\frac{6.022\times {10}^{23}}{16}\times 2$ atoms $=\frac{6.022\times {10}^{23}}{8}$ atoms

$\frac{1}{64}$ moles of sulphur has $8\times \frac{6.022\times {10}^{23}}{64}=\frac{6.022\times {10}^{23}}{8}$ atoms
Note: Sulphur is found in the form of $S_8$.