Answer:
25.1 grams to 3 significant figures.
Explanation:
2Al(s) + 3Cl2(g) → 2AlCl3(s)
Using the molar masses:
2*26.982 g Al reacts with 3*2*35.45 g of Cl2
53.964 g Al reacts with 212.7 g Cl2
So 15 g Al reacts with (212.7 / 53.964) * 15 = 59.123 g Cl2
But we only have 20 g of chlorine so the mass of Aluminium which reacts with this is( 53.964/ 212.7) * 20
= 5.074 g.
So the maximum mass of aluminium chloride = 5.074 + 20
= 25.074 g. (answer)