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 SnCrO4

Answer 1

To find the formula mass of tin(ii) chromate we multiply the subscript by the molar mass of that particulat element. If there are no subscript we multiply by 1.

`\begin{gathered} Sn:118.7gmol^(-1)*1=118.7amu \\ Cr:52.0gmol^(-1)*1=52.0amu \\ O:16.0gmol^(-1)*4=64amu \end{gathered}`

Total mass or formula mass of the compound is:

`118.7+52+64=234.7amu`

Dividing each element by the formula mass of the compound gives:

`\begin{gathered} Sn:(118.7amu)/(234.7amu)*100=50.6\% \\ \\ Cr:(52amu)/(234.7amu)*100=22.1\% \\ \\ O:(64amu)/(234.7amu)*100=27.3\% \end{gathered}`