Question

Which one of the following has least mass?

• A. $2.24L$ of $S{O}_2$ at $S.T.P$
• B. $16g$ of $C{H}_4$
• C. $6.02\times {10}^{22}{O}_2$ molecules
• D. $0.5mole{O}_3$

Answer 1

Answer: (C)

$6.02\times {10}^{22}{O}_2$ molecules

1) $2.24L$ of $S{O}_2$

Moles of $S{O}_2=\frac{2.24}{22.4}=0.1\Rightarrow mass=0.1\times 64=6.4gm$

2) $16gC{H}_4$

3) $6.02\times {10}^{22}{O}_2$ molecules

Number of molecules $=\frac{6.022\times {10}^{22}}{6.022\times {10}^{23}}=0.1$

$mass=0.1\times 32=3.2g$

4) $0.5$ mole of $O_3$

Mass of $O_3=\frac{1}{2}\times 48=24gm$

$\therefore 6.02\times {10}^{22}{O}_2$ molecule have least mass.