Answer:
6.3 moles
Explanation:
From the balanced equation of reaction:
[tex]2Al + 3Cl_2 --> 2AlCl_3[/tex]
2 moles of aluminium reacts with 3 moles of chlorine gas to form 2 moles of AlCl3.
Therefore, 1 mole of chlorine will require: 2 x 1/3 = 0.67 mole of aluminium.
Hence, 0.67 mole of aluminium will be needed for 1 mole of chlorine. If 7 moles of aluminium is present, then:
7 - 0.67 = 6.33 moles of aluminium will be left.
To the nearest 0.1, it means 6.3 moles of aluminium will be left.