How do you calculate the percent composition by mass of each element in Al(OH_)3?

1 Answer
May 17, 2018

Al = 34.62%

O = 61.54%

H = 3.85%

Explanation:

The Percentage Composition by Mass of Each Element is indicated by :-

"Molar mass of The Element"/"Molar Weight of the Total Compound" xx 100%

So, The Molar Weight of the Total Compound = {27 + 3 xx (16 + 1)} g mol^-1 = (27 + 51) g mol^-1 = 78 g mol^-1

So, Percentage Composition of Aluminium = 27/78 xx 100% = 34.62% (approx.)

Percentage Composition of Oxygen = (3 xx 16)/78 xx 100% = 61.54% (approx.)

And Percentage Composition of Hydrogen = (3 xx 1)/78 xx 100% = 3.85% (approx.)