4 When aluminium hydroxide is heated it decomposes and produces aluminium oxide and water. The equation for the reaction is shown. 4Al(OH)3 The relative molecular mass of aluminium hydroxide is 78. [A: O, 16; AZ, 27; H, 1]

(a) (i) Calculate the relative molecular mass, Mr, of aluminium oxide.

(ii) Complete the following sentences. 2AL2O3 + 6H₂O
M =..................

312g of the aluminium hydroxide produces g of water. 7.8g of the aluminium hydroxide produces .....................g of aluminium oxide and ............g of aluminium oxide.​