Question

Mass of aluminium needed to combine with 19.2 gram of oxygen to make Aluminium oxide is

Answer 1

No. of moles of oxygen = 19.2/32 = 0.6

The reaction that occurs is :-

4 Al + 3 O2 = 2 Al203

3 moles oxygen (molar mass = 32 gram ) react with 4 mole aluminum.

=> 1 mole --------------------4/3 mole aluminum

=> 0.6----------------------0.8 mole aluminum.

Now, mass of 0.8 mole aluminum = 27 × 0.8 = 21.6 gram.