Question #5c707

Ammonium phosphate, `("NH"_color(red)(4))_color(blue)(3)"PO"_4`, is an ionic compound made up of ammonium cations, `"NH"_4^(+)`, and phosphate anions, `"PO"_4^(3-)`.

As you can see from the compound's chemical formula, one formula unit of ammonium phosphate contains

• three ammonium cations, `color(blue)(3) xx "NH"_4^(+)`
• one phosphate anion, `1 xx "PO"_4^(3-)`

This of course means that one mole of ammonium phosphate will contain `color(blue)(3)` moles of ammonium cations and `1` mole of phosphate anions.

Now, each ammonium cation is made up of

• one atom of nitrogen, `1 xx "N"`
• four atoms of hydrogen, `color(red)(4) xx "H"`

Since one mole of ammonium cations will contain `color(red)(4)` moles of hydrogen atoms, it follows that one mole of ammonium phosphate will contain a total of

`color(blue)(3) color(darkred)(cancel(color(black)("moles NH"_4^(+)))) * (color(red)(4)color(white)(a)"moles of H")/(1color(darkred)(cancel(color(black)("mole NH"_4^(+))))) = color(green)(|bar(ul(color(white)(a/a)color(black)("12 moles of H")color(white)(a/a)|)))`

Therefore, you can say that every mole of ammonium phosphate contains a total of `12` moles of hydrogen atoms.

You can expand this to say that for any number of moles of ammonium chloride given to you, `n`, the number of moles of hydrogen atoms can be found by multiplying `n` by `12`

`n color(red)(cancel(color(black)("moles"color(white)(a)("NH"_4)_3"PO"_4))) * "12 moles H"/(1color(red)(cancel(color(black)("mole"color(white)(a)("NH"_4)_3"PO"_4)))) = (12 * n)color(white)(a)"moles H"`