Question

Which among the following has maximum mass?

• A. $1\mathrm{g}$ of $\mathrm{Fe}$
• B. $0.1$ mole of ammonia
• C. ${10}^{22}$ atoms of carbon
• D. ${10}^{22}$ molecules of carbon dioxide

Answer 1

The correct option is B

$0.1$ mole of ammonia

Explanation for the correct option:

Option B: $0.1$ mole of Ammonia

Calculate the mass of $\mathbf{0}\mathbf{.}\mathbf{1}$ mole of ammonia $\mathbf{\left(}{\mathbf{NH}}_{\mathbf{3}}\mathbf{\right)}$:

1. $\mathrm{m}=\mathrm{n}\times \mathrm{M}$, where $\mathrm{n}$ is the number of moles, $\mathrm{m}$ is the given mass and $\mathrm{M}$ is the molar mass.
2. Molar mass of $\mathbf{\left(}{\mathbf{NH}}_{\mathbf{3}}\mathbf{\right)}$ = $17\mathrm{u}$
3. Mass of $\mathbf{0}\mathbf{.}\mathbf{1}$ mole of ammonia $\mathbf{\left(}{\mathbf{NH}}_{\mathbf{3}}\mathbf{\right)}$ = $0.1\times 17=1.7\mathrm{g}$

Explanation for the incorrect option:

Option A:

1. The mass of $\mathbf{1}\mathbf{g}$ of $\mathbf{Fe}$ is $1\mathrm{g}$. This is lesser than the mass of $\mathbf{0}\mathbf{.}\mathbf{1}$ mole of Ammonia $\left(1.7\mathrm{g}\right)$.
2. Hence Option A is incorrect.

Option C: Mass of ${10}^{22}$ atoms of carbon

1. One mole of any substance contains $\left(6.022\times {10}^{23}\right)$ particles. …… (Avogadro's number)
2. $1$ mole carbon = $6.022\times {10}^{23}$atoms
3. ${10}^{22}$ atoms of carbon $=\frac{{10}^{22}}{6.022\times {10}^{23}}=0.0166$ mole carbon
4. $1$ mole carbon = $12\mathrm{g}$ carbon
5. $0.0166$ mole carbon $=0.0166\times 12=0.1992\mathrm{g}$ carbon.
6. Thus, the mass of ${10}^{22}$ atoms of carbon is $0.1992\mathrm{g}$, which is lesser than $\mathbf{0}\mathbf{.}\mathbf{1}$ mole of Ammonia $\left(1.7\mathrm{g}\right)$.

Option D: The mass of ${\mathbf{10}}^{\mathbf{22}}$ molecules of Carbon dioxide:

1. One mole of any substance contains $6.022\times {10}^{23}$ particles. …… (Avogadro's number)
2. $6.022\times {10}^{23}$ molecules of carbon dioxide = $1$ mole carbon dioxide
3. ${10}^{22}$ molecules of Carbon dioxide $=\frac{{10}^{22}}{6.022\times {10}^{23}}=0.0166$ mole of Carbon dioxide
4. $1$ mole carbon dioxide = $44\mathrm{g}$ carbon dioxide
5. $0.0166$ mole Carbon dioxide $=0.0166\times 44=0.7304\mathrm{g}$
6. Thus, the mass of ${10}^{22}$ molecules of carbon dioxide is $0.7304\mathrm{g}$, which is lesser than $\mathbf{0}\mathbf{.}\mathbf{1}$ mole of Ammonia $\left(1.7\mathrm{g}\right)$.

Thus, $\mathbf{0}\mathbf{.}\mathbf{1}$ mole of ammonia has the highest mass.