J.R. S. answered 02/07/19
Ph.D. University Professor with 10+ years Tutoring Experience
Assuming the reaction is between solid aluminum and gaseous chlorine, the balance equation would be...
2Al(s) + 3Cl2(g) ===> 2AlCl3(s)
moles of Al used = 45 g Al x 1 mole Al/27 g = 1.67 moles Al = 1.7 moles Al
Assuming that Cl2(g) is not limiting in the reaction, the formation of AlCl3 will depend only on Al present.
Thus, moles AlCl3 produced = 1.7 moles Al x 2 moles AlCl3/2 moles Al = 1.7 moles AlCl3 produced