We use the given masses of the reactants to calculate the moles of Mn and Cl. Empirical formula represents the simplest mole ratio of atoms present in a compound.
Moles of Mn = [tex] 12.99 g Mn * \frac{1 mol Mn}{54.94 g Mn} = 0.236 mol Mn [/tex]
Moles of Cl = [tex] 25.16 g Cl_{2} *\frac{1 mol Cl_{2}}{70.91 g Cl_{2}} * \frac{2 mol Cl}{1 mol Cl_{2}} [/tex] = 0.710 mol Cl
Simplest mole ratio: [tex] Mn_{\frac{0.236}{0.236}}Cl_{\frac{0.710}{0.236}} [/tex]
So the empirical formula is [tex] MnCl_{3} [/tex]
