Question

Rearrange the following ($I$ to $IV$) in the order of increasing masses and choose the correct answer. (Atomic masses : $N=14,O=16,Cu=63$)
I. $1$ molecule of oxygen
II. $1$ atom of Nitrogen
III. $1\times {10}^{-10}$ (g molecular weight of oxygen)
IV. $1\times {10}^{-10}$ (g atomic weight of copper)

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

Answer 1

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

1. Molecule of oxygen, $O_2=32u=32\times 1.66\times {10}^{-24}g$

2. $1$ atom of $N=14u=14\times 1.66\times {10}^{-24}g$

3. $1\times {10}^{-10}$ (g. molecular wt of $O_2$) $=1\times {10}^{-10}\times 32$

$=32\times {10}^{-10}$

4.$1\times {10}^{-10}$ (g.molecular wt of Cu)$=1\times {10}^{-10}\times 63$

$=63\times {10}^{-10}$

So, Order of increasing masses

$2<1<3<4$

Hence, the correct option is $A$