How many grams of chlorine gas can be produced from the decomposition of 73.4
g. of aucl3 by this reaction: 2aucl3 > 2 au + 3 cl2

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