The first step we have to follow is to find the molar mass of FeCl2 using the atomic masses of each element:
[tex]\begin{gathered} Fe=55.845g/mol \\ Cl=35.45g/mol\times2=70.9g/mol \\ FeCl_2=126.745g/mol \end{gathered}[/tex]It means that each mole of FeCl2 has a mass of 126.745g/mol.
Use the molar mass to find the mass of the given amount of moles:
[tex]869molFeCl_2\cdot\frac{126.745gFeCl_2}{1molFeCl_2}=110,141.405gFeCl_2[/tex]It means that there are 110,141.405 grams of FeCl2.
In scientific notation it would be 1.10x10^5g.
