An aluminum-containing compound has the formula Mg x Al y O 4 and is 44.98 % oxygen by mass. What is the value of the subscripts x and y ?

Explanation:

Given that:- The percentage by mass of oxygen in the compound is 44.98 %

Form the formula, it can be seen that:-

4 moles of oxygen atom are present in 1 mole of the compound.

Molar mass of oxygen = 16 g/mol

Mass of 4 moles of oxygen = 4 mol x 16 g/mol = 64 g

Mass of the compound = = 142 g

Mass of aluminum + Mass of magnesium = Total mass - Mass of oxygen = 142 g - 64 g = 78 g

Molar mass of aluminium = 27 g/mol

Moles of aluminum = y moles

Molar mass of magnesium = 24 g/mol

So, 24x + 27 y = 78

Thus, x = 1 and y = 2 (One solution )

Thus, the formula is