Question

Find the formula mass of the compound, then divide the individual element total by the total mass-move the decimal over two to change it to percentage FeCl3

Answer 1

We first look up in the periodic table the molar mass of each individual element:

Fe: 55.84 g/mol

Cl: 35.45 g/mol

Then we calculate the molar mass of the compound:

`\rbrack M_(FeCl_3)=M_(Fe)+3.M_(Cl)=55.84(g)/(mol)+3.(35.45(g)/(mol))=162.19(g)/(mol)`

Finaly we calculate the percentage:

`\begin{gathered} Fe=(55.84(g)/(mol))/(162.19(g)/(mol))x100=34.4\% \\ Cl=\frac{3.\text{ }35.45(g)/(mol)}{162.19(g)/(mol)}x100=65.6\% \end{gathered}`

So finally, the percentages of each element in the molecule are:

Fe: 34.4%

Cl: 65.6%