Question

A newly synthesized compound has the molecular formula ${\mathbf{ClF}}_{\mathbf{2}}{\mathbf{O}}_{\mathbf{2}}{\mathbf{PtF}}_{\mathbf{6}}$. Compute, to four significant figures, the mass percentage of each of the four elements in this compound.

Short answer

The mass percentages of chlorine, oxygen, fluorine, and platinum are 8.553%, 7.720%, 36.67%, and 47.063%, respectively.

Step-by-step solution

Calculation of molar mass of  ClF2O2PtF6

The molar mass of a compound can be calculated by adding the molar masses of each atom in the compound.

The molar mass of chlorine, $\text{Cl = 35.453}{\text{gmol}}^{-1}$.

The molar mass of oxygen, $\text{O = 15.999}{\text{gmol}}^{-1}$.

The molar mass of fluorine, $\text{F = 18.998}{\text{gmol}}^{-1}$.

The molar mass of platinum, $\text{Pt = 195.084}{\text{gmol}}^{-1}$.

Therefore, the molar mass of the given compound;

$\begin{array}{rcl}{\text{ClF}}_2{\text{O}}_2{\text{PtF}}_6& =& \left(1\times 35.453{\text{gmol}}^{-1}\right)+\left(8\times 18.998{\text{gmol}}^{-1}\right)+\left(2\times 15.999{\text{gmol}}^{-1}\right)\left(1\times 195.084{\text{gmol}}^{-1}\right)\\ & =& 414.519{\text{gmol}}^{-1}\end{array}$

Step 2: Mass percentage of each element.

The mass percentage of chlorine;

${\text{m}}_1\%=\frac{{\text{m}}_1}{\text{M}}\times 100$

Here, ${\text{m}}_1$is the molar mass of chlorine and localid="1663404300978" $\text{M}$ is the molar mass of ${\text{ClF}}_2{\text{O}}_2{\text{PtF}}_6$

Substituting the values, one gets;

$\begin{array}{rcl}{\text{m}}_1\%& =& \frac{35.453}{\text{414.519}}\times 100\\ & =& 8.553\end{array}$

Similarly, the mass percentage of oxygen is;

${\text{m}}_{\text{2}}\%=\frac{{\text{m}}_2}{\text{M}}\times 100$

As there are two oxygen atoms;

$\begin{array}{rcl}{\text{m}}_{\text{2}}\%& =& \frac{2\times 15.999}{\text{414.519}}\times 100\\ & =& 7.7\end{array}$

The mass percentage offluorine is;

As the total number of fluorine atoms in the compound is 8.

$\begin{array}{rcl}{\text{m}}_3\%& =& \frac{{\text{m}}_3}{\text{M}}\times 100\\ & =& \frac{8\times 18.998}{414.519}\times 100\\ & =& 36.67\end{array}$

The mass percentage of platinum,

$\begin{array}{rcl}{\text{m}}_4\%& =& \frac{{\text{m}}_4}{\text{M}}\times 100\\ & =& \frac{195.084}{414.519}\times 100\\ & =& 47.063\end{array}$