After a mixture of iron and sulfur are heated and then cooled a magnet no longer attracts the iron how would you classify the resulting material

Iron is a magnetic substance which is attracted by magnetic field. In a mixture, the properties of elements are retained.  When a mixture of iron filling and sulfur are present, iron can be attracted towards a magnet. When the mixture of iron and sulfur is heated, iron reacts chemically with sulfur to form a new compound iron sulfide. Iron sulfide does not retain the properties of individual elements iron and sulfur. So, the mixture of iron and sulfur after heating will no longer be attracted towards a magnet as a new compound iron sulfide will be formed.

calculate how many grams of ammonia can be produced from 4.21 grams of

n2 + 3h2 = 2nh3

my answer:

25.0g n2 x (1 mol/ 28.0gn2) x (2 mol nh3/ 1 mol n2) x (17.0g nh3/ 1 molnh3) = 30.36g n2

25.0g h2 x (1 mol h2/ 2.00g h2) x (2 mol nh3/ 3 mol h2) x (17.0g nh3/ 1 mol nh3) = 141.67g h2

lr = n2

the correct answer would be b. amelia, because the particals of gas move really fast (charged particals) and gas also has a lot of room (particals move independently) so the only answer that has both of those is amelia's.