Given 20.0 g of (NH4)3 PO3 how many moles is this? How many formula units is it? How many hydrogen atoms are present?

no of moles = (mass) ÷ molar mass

you get the molar mass from the periodic table

n = 20.0g ÷ ( 149.09 g/mol )

= 0.134 mol

number of formula units = number of moles × (6.022×10^23)

= 8.07×10^22 units

number of hydrogen atoms in (NH4)3 PO3 = 12 × number of formula units

= 9.68×10^23 hydrogen atoms

i think it's c. if you look search electronic symbol on google and then click on wiki it shows you a