1) first, we have to convert the grams to moles of AuCl3 using the molar mass of the molecule.
molar mass of AuCl3= 197 + (35.5 x 3)= 303.5 g/mol
73.4 g (1 mol AuCl3/ 303.5 g)= 0.242 moles
2) now. let's convert moles of AuCl3 to moles of chlorine gas (Cl2) using the mole-mole ratio
0.242 mol AuCl3 (3 mol Cl2/ 2 mol AuCl3)= 0.363 mol Cl2
3) finally, we convert moles to grams using the molar mass of Cl2.
molar mass of Cl2 = 35.5 x 2= 71.0 g/mol
0.363 mol Cl2 ( 71.0 g/ 1 mol)= 25.8 grams
