Question

Rearrange the following ($I$ to $IV$ ) in the order of increasing masses:
I) $0.5$ mole of $O_3$
II) $0.5gm$ atom of oxygen
III) $3.011\times {10}^{23}$ molecules of $O_2$
IV) $5.6$ litre of $C{O}_2$ at $1atm$ and $273K$

• A. $II<IV<III<I$
• B. $II<I<IV<III$
• C. $IV<II<III<I$
• D. $I<II<III<IV$

Answer 1

The correct option is A $II<IV<III<I$

$I)\text{mass of substance}=\text{moles of substance}\times \text{molar mass of substance}$

$\text{mass of}{O}_3=0.5\times 48=24g$

$II)\text{1 gm atom}=1\text{mole}$

$\text{mass of}O=0.5\times 16=8g$

$III)\text{1 mole}=6.022\times {10}^{23}\text{molecules}$

$\text{number of moles of}{O}_2=\frac{3.011\times {10}^{23}}{6.022\times {10}^{23}}=0.5$

$\text{mass of}{O}_2=0.5\times 32=16g$

$IV)\text{volume of 1 mole at NTP}=22.4L$

$\text{moles of}C{O}_2=\frac{5.6}{22.4}=0.25$

$\text{mass of}C{O}_2=0.25\times 44=11g$