We are required to find how many formula units of potassium phosphate in 42.5 g
potassium phosphate (K3PO4) have molar mass of 212.27 g/mol
We are given the mass in grams = 42.5g
Now we can find the formula units.
n = m/M where m is the mass and M is the molar mass
n = 42.5g/212.27 g/mol
n = 0.2002 mol
There are 6.022x10^23 formula units in 1 mole.
So to get the number of formula unit, multiply avogadros constant with number of moles
formula units = 6.022x10^23 x 0.2002
formula units = 1.206x10^23