Answer to Question #235463 in Chemistry for Dotun

Question

The percent of aluminum in the compound, Al2X3, is 18.56 %. What is the molar mass of element X ?

Answer 1

Solution:

Al₂X₃

%Al = (2 × Molar mass of Al / Molar mass of Al₂X₃) × 100%

18.56% = (2 × 26.98 g Al mol^-1 / Molar mass of Al₂X₃) × 100%

0.1856 = (53.96 / Molar mass of Al₂X₃)

Molar mass of Al₂X₃ = 53.96 / 0.1856 = 290.73

Molar mass of Al₂X₃ = 2 × Molar mass of Al + 3 × Molar mass of X

290.73 = 2 × 26.98 + 3 × Molar mass of X

290.73 = 53.96 + 3 × Molar mass of X

Molar mass of X = (290.73 - 53.96) / 3 = 78.92 g/mol

Answer: The molar mass of element X is 78.92 g/mol