Question

Which has maximum number of atoms of oxygen?

• A. $10\mathrm{mL}{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$
• B. $0.1\mathrm{mole}\mathrm{of}{\mathrm{V}}_2{\mathrm{O}}_5$
• C. $12\mathrm{g}{\mathrm{O}}_3\left(\mathrm{g}\right)$
• D. $12.044\times {10}^{22}\mathrm{molecules}\mathrm{of}{\mathrm{CO}}_2$

Answer 1

The correct option is D

$12.044\times {10}^{22}\mathrm{molecules}\mathrm{of}{\mathrm{CO}}_2$

Explanation for correct option

(D) $\mathbf{12}\mathbf{.}\mathbf{044}\mathbf{\times }{\mathbf{10}}^{\mathbf{22}}\mathbf{}\mathbf{molecules}\mathbf{}\mathbf{of}\mathbf{}{\mathbf{CO}}_{\mathbf{2}}$

Atom

• A chemical element is uniquely defined by its atoms, which are small units of atoms.
• A central nucleus that is often surrounded by one or more electrons makes up an atom.
• The charge of every electron is negative.
• The positively charged nucleus is made up of one or more relatively heavy protons and neutrons.

$\mathbf{12}\mathbf{.}\mathbf{044}\mathbf{\times }{\mathbf{10}}^{\mathbf{22}}\mathbf{}\mathbf{molecules}\mathbf{}\mathbf{of}\mathbf{}{\mathbf{CO}}_{\mathbf{2}}$

• The number of oxygen atoms in $12.044\times {10}^{22}\mathrm{molecules}\mathrm{of}{\mathrm{CO}}_2$ is as follows:

$\begin{array}{rcl}\mathrm{Number}\mathrm{of}\mathrm{oxygen}\mathrm{atoms}& =& 2\times 12.044\times {10}^{22}\\ & =& 2.4088\times {10}^{23}\mathrm{atom}\end{array}$

Explanation for incorrect options

(A) $\mathbf{10}\mathbf{}\mathbf{mL}\mathbf{}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}\mathbf{\left(}\mathbf{l}\mathbf{\right)}$

• The density of water $=1\mathrm{g}{\mathrm{mL}}^{-1}$
• $10\mathrm{mL}{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$ (Water) is equal to $10\mathrm{g}$ water.
• The number of oxygen atoms is as follows:

$\begin{array}{rcl}\mathrm{Number}\mathrm{of}\mathrm{oxygen}\mathrm{atoms}& =& \frac{10}{18}\times 6.022\times {10}^{23}\\ & =& 3.35\times {10}^{23}\mathrm{atom}\end{array}$

(B) $\mathbf{0}\mathbf{.}\mathbf{1}\mathbf{}\mathbf{mole}\mathbf{}\mathbf{of}\mathbf{}{\mathbf{V}}_{\mathbf{2}}{\mathbf{O}}_{\mathbf{5}}$

• The number of oxygen atoms is as follows:

$\begin{array}{rcl}\mathrm{Number}\mathrm{of}\mathrm{oxygen}\mathrm{atoms}& =& 5\times 0.1\times 6.022\times {10}^{23}\\ & =& 3\times {10}^{23}\mathrm{atom}\end{array}$

(C) $\mathbf{12}\mathbf{}\mathbf{g}\mathbf{}{\mathbf{O}}_{\mathbf{3}}\mathbf{\left(}\mathbf{g}\mathbf{\right)}$

• The number of oxygen atoms is as follows:

$\begin{array}{rcl}\mathrm{Number}\mathrm{of}\mathrm{oxygen}\mathrm{atoms}& =& 3\times \frac{12}{48}\times 0.1\times 6.022\times {10}^{23}\\ & =& 1.5\times {10}^{23}\mathrm{atom}\end{array}$

Therefore, the correct option is (D) $\mathbf{12}\mathbf{.}\mathbf{044}\mathbf{\times }{\mathbf{10}}^{\mathbf{22}}\mathbf{}\mathbf{molecules}\mathbf{}\mathbf{of}\mathbf{}{\mathbf{CO}}_{\mathbf{2}}$.