One mole of aluminum chloride (AlCl3), 26.98 grams of aluminum (Al), and 106.4 grams of chlorine (Cl). What is the percent composition of aluminum in aluminum chloride?

A 3.700%

B 20.22%

C 25.40%

D 79.81%

1 answer

total mass = 26.98 + 106.4 = 133.38
100 * ( 26.98/133.38) = 20.2279
which I call 20.23% but 20.22% is close enough :)