Respuesta :

Answer:

28.17 %

Explanation:

In the question we are required to determine the percent by mass of nitrogen in  (NH₄)₃PO₄.

  • To calculate the percent by mass of an element in a compound we use the formula;
  • % by mass =(Mass of the element÷ Relative formula mass of the compound)100

In this case;

  • Atomic mass of nitrogen is 14.0 g/mol

But; There are three nitrogen atoms in (NH₄)₃PO₄.

Therefore; Mass of nitrogen in (NH₄)₃PO₄ = 14.0 × 3

                                                                     = 42 g

The relative formula mass of (NH₄)₃PO₄ = 149.0867 g/mol

Thus;

% by mass of N = (42 g ÷ 149.0867 g/mo)× 100%

                          = 28.17 %

Therefore, the % by mass of N is (NH₄)₃PO₄ is 28.17%