Answer to Question #206774 in Chemistry for Shaunti

Question

 X has a molar mass of 46.31, what is the percentage composition by mass of X in X₃PO₄?

 

Answer 1

A molar mass of X₃PO₄ equals:

Mr(X₃PO₄) = (3 × 46.31 g/mol) + 31 g/mol + (3 × 16 g/mol) = 217.93 g/mol

The percentage composition by mass of X in X₃PO₄ equals:

w % = [Mr(X) / Mr(X₃PO₄)] × 100 % = [46.31 g/mol / 217.93 g/mol] × 100 % = 21.25 %

Answer: 21.25 %