Aluminum chloride - It does not have the prefix "tri-" since it is ionic. The other compounds listed in the question are covalent and require prefixes.
<span>Total mass = 3.64 + 2.87 + 4.13 = 10.64 g
Mass percent of NH4Cl = (mass of NH4Cl/ Total mass) x 100 = (2.87 g/10.64g) x 100 = 27.0 % mass of NH4Cl</span>